Control device for controlling tomosynthesis imaging, imaging apparatus, imaging system, control method, and program for causing computer to execute the control method

ABSTRACT

In tomosynthesis imaging for obtaining a tomosynthesis image from a projected image group captured by irradiating an object with X-rays from a plurality of different angles by using an X-ray generation unit and an X-ray detection unit, in association with a process for setting data of a projected image group as a reject, data of a tomosynthesis image generated on the basis of the projected image group is set as a reject.

TECHNICAL FIELD

The present disclosure relates to a control device for controllingtomosynthesis imaging for capturing projected images of a plurality offrames and obtaining a tomosynthesis image from the plurality ofprojected images, an imaging apparatus, an imaging system, a controlmethod, and a program for causing a computer to execute the controlmethod.

BACKGROUND ART

In tomosynthesis imaging, an X-ray generation apparatus irradiates aperson being examined with X-rays at different angles while being movedand an X-ray detector detects X-rays transmitted through the object,thereby allowing continuous capture of projected images of a pluralityof frames having different imaging angles. The captured projected imagesof the plurality of frames are shifted so that the preset centerpositions thereof coincide with each other to make corresponding pixelsoverlap each other, thereby executing the reconstruction of atomosynthesis image that is a tomographic image of a certain crosssection of the person being examined (PTL 1). In addition, thereconstruction is re-performed with the reconstruction method, thefilter settings, the slice pitch, and the number of slices changed,enabling a plurality of tomosynthesis images to be generated forprojected images acquired in a single imaging session. The generatedplurality of tomosynthesis images are subjected to window adjustment orgeometric transformation processing, and are then used for diagnosis.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Laid-Open No. 2000-46760

SUMMARY OF INVENTION Technical Problem

In a case where at least one tomosynthesis image is reconstructed on theimaging apparatus side, the tomosynthesis image is output to a PACS, animage viewer, a printer, or the like via a network after the end of anexamination. In this case, it is conceivable that an image obtained as aresult of imaging failure or a tomosynthesis image that does not need tobe output is set as a reject, thereby switching ON/OFF of the outputtarget. However, if a group of projected images on which a tomosynthesisimage is based is set as rejects, the tomosynthesis image may also havea certain problem.

Solution to Problem

Accordingly, a control device for controlling tomosynthesis imagingaccording to an embodiment of the present invention is a control devicefor controlling tomosynthesis imaging for obtaining a tomosynthesisimage from a projected image group captured by irradiating an objectwith X-rays from a plurality of different angles by using an X-raygeneration unit and an X-ray detection unit. The control device includesa communication circuit that transmits at least either of data of atomosynthesis image and data of the projected image group to an externaldevice, setting means for setting at least one of the data of thetomosynthesis image or the data of the projected image group as areject, and output control means for limiting transmission of the dataset as a reject to the external device. In response to the data of theprojected image group being set as a reject, the setting means sets dataof a tomosynthesis image generated on the basis of the projected imagegroup as a reject.

Advantageous Effects of Invention

This can facilitates a reject setting of a tomosynthesis imagingtechnique, and enables image output ON/OFF to be set.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a configuration diagram of an X-ray imaging system accordingto an embodiment of the present invention.

FIG. 2 is a system configuration diagram of tomosynthesis imagingaccording to the embodiment of the present invention.

FIG. 3 is a diagram illustrating position information acquired duringtomosynthesis imaging.

FIG. 4 is a configuration diagram of an imaging control unit accordingto the embodiment of the present invention.

FIG. 5 is a hardware configuration diagram of the imaging control unitaccording to the embodiment of the present invention.

FIG. 6 is a flowchart diagram illustrating a process flow according tothe embodiment of the present invention from the start to the end of anexamination during tomosynthesis imaging.

FIG. 7 is a flowchart diagram illustrating a process flow according tothe embodiment of the present invention from the end of the examinationto the completion of image output.

FIG. 8 is a diagram illustrating a patient information input screenaccording to the embodiment of the present invention.

FIG. 9 is a diagram illustrating an imaging technique selection screenaccording to the embodiment of the present invention.

FIG. 10 is a diagram illustrating an imaging screen according to theembodiment of the present invention.

FIG. 11 is a diagram illustrating a reconstruction screen according tothe embodiment of the present invention.

FIG. 12 is a diagram illustrating an oblique cross section displayscreen on the reconstruction screen according to the embodiment of thepresent invention.

FIG. 13 is a flowchart diagram illustrating a process flow according tothe embodiment of the present invention from the start of irradiationfor projected images to the display of a reconstruction screen.

FIG. 14(a) is a diagram illustrating the imaging screen according to theembodiment of the present invention in a case where there is nonotification of position information. FIG. 14(b) is a diagramillustrating the imaging screen according to the embodiment of thepresent invention in a case where imaging is interrupted at less than0°.

FIG. 15 is a diagram illustrating the reconstruction screen according tothe embodiment of the present invention in a case where imaging isinterrupted at 0° or greater.

FIG. 16 is a diagram illustrating the configuration of an imagingcontrol device 107 according to another embodiment of the presentinvention.

FIG. 17 is a diagram illustrating an example in a case where adiscrepancy occurs between the number of projected image frames and thenumber of pieces of position information.

FIG. 18 is a diagram illustrating the reconstruction process screenaccording to the embodiment of the present invention in a case where acorrection process is executed.

FIG. 19 is a diagram illustrating valid frames and invalid frames in atomosynthesis image.

FIG. 20 includes diagrams illustrating a screen showing a reproductionprocessing portion on the reconstruction screen according to theembodiment of the present invention.

FIG. 21 is a diagram illustrating a process flow related to windowprocessing according to the embodiment of the present invention from anexecution of a reconstruction process until a tomosynthesis image isdisplayed.

FIG. 22 includes diagrams illustrating a screen showing a windowadjustment portion on the reconstruction screen according to theembodiment of the present invention.

FIG. 23 is a diagram illustrating a process flow according to theembodiment of the present invention from the confirmation ofreconstruction until an image is displayed as a preview.

FIG. 24 includes diagrams illustrating a single-view display screen anda multi-view display screen on the imaging screen according to theembodiment of the present invention.

FIG. 25 is a diagram illustrating a process flow according to theembodiment of the present invention from the start of reject andreconstruction processes until a reject setting is performed.

FIG. 26 is a diagram illustrating a reject reason input screen accordingto the embodiment of the present invention.

FIG. 27 is a diagram illustrating the imaging screen according to theembodiment of the present invention when a re-imaging process iscompleted.

FIG. 28 is a diagram illustrating the imaging screen according to theembodiment of the present invention when a reject process is completed.

FIG. 29 is a diagram illustrating an example relationship betweenprojection angles of projected images and oblique cross sectionsaccording to an embodiment.

DESCRIPTION OF EMBODIMENTS

The configuration and operation of an X-ray imaging system according toan embodiment of the present invention will be described hereinafterwith reference to FIGS. 1 to 29.

FIG. 1 illustrates the configuration of an X-ray imaging systemaccording to an embodiment of the present invention. An X-ray imagingsystem 101 includes an X-ray generation unit 102, a movement mechanism1061, a column 1062, an X-ray irradiation switch 103, an X-ray controlunit 104, an imaging table 105, an X-ray detector 106, an imagingcontrol device 107, an operation unit 108, and a display unit 109. TheX-ray detector 106 and the imaging control device 107 collectively serveas an X-ray imaging apparatus, in particular. The X-ray generation unit102 and the X-ray control unit 104 collectively serve as an X-raygeneration apparatus, in particular. The movement mechanism 1061, thecolumn 1062, and a movement mechanism control unit 1063 collectivelyserve as an imaging system holding apparatus. The term imaging system,as used herein, is used to include the X-ray generation apparatus andthe X-ray imaging apparatus, namely, the X-ray generation unit 102 andthe X-ray detector 106. The X-ray generation apparatus and the imagingsystem holding unit may be collectively referred to as an X-raygeneration apparatus.

The X-ray generation unit 102 performs X-ray irradiation. Further, theX-ray generation unit 102 transmits imaging execution conditions such astube voltage and tube current and position information such as animaging angle and an X-ray source moving distance to the X-ray controlunit 104 in accordance with X-ray irradiation. Further, the X-raygeneration unit 102 receives default imaging conditions and defaultposition information from the X-ray control unit 104, and performs animaging preparation process.

The movement mechanism 1061 is capable of linearly moving the X-raydetector 106 in the direction of the axis of the body of the object, forexample. The column 1062 includes a movement mechanism that movablysupports the X-ray generation unit 102, and is capable of moving theX-ray generation unit 102 along an arc in the direction of the axis ofthe body of the object.

The movement mechanism control unit 1063 controls the movement of themovement mechanism 1061 of the X-ray detector and the column 1062. Themovement mechanism control unit 1063 is capable of moving the movementmechanism 1061 and the column 1062 in synchronization with each other.Here, the movement mechanism 1061 and the column 1062 are moved insynchronization with each other, the X-ray generation unit 102 is movedin a first direction, and the X-ray detector 106 is moved in a directionopposite to the first direction, thereby providing an execution oftomosynthesis imaging for obtaining projected images from a plurality ofdirections.

Further, the movement mechanism control unit 1063 is connected to theX-ray control unit 104. The movement mechanism control unit 1063receives information on the timing of X-ray irradiation, and outputsposition information on the X-ray generation unit 102 and the X-raydetector 106 at this timing to the X-ray control unit 104. For example,in the case of intermittent emission of pulsed X-rays, positioninformation on the X-ray generation unit 102 and the X-ray detector 106at the start of emission of the pulsed X-rays, at the end of theemission, or at a certain time during the emission is output.

The X-ray irradiation switch 103 transmits an irradiation startnotification and an irradiation end notification to the X-ray controlunit 104. When pressed by an operator, the X-ray irradiation switch 103transmits an irradiation start notification. When released by theoperator, the X-ray irradiation switch 103 transmits an irradiation endnotification. When the X-ray irradiation switch 103 is being pressed, asequence of projected images is captured while the X-ray generation unit102 and the X-ray detector 106 are moved. During the capture of asequence of projected images, for example, The X-ray generation unit 102performs X-ray irradiation while being moved over a range from minus 30degrees to plus 30 degrees. In this case, if the pressing of the X-rayirradiation switch 103 is stopped in the middle of the range at the timewhen an angle of plus 10 degrees is reached, the capture of projectedimages is interrupted. Note that a 0-degree position is established whenthe column 1062 extends in the vertical direction.

The X-ray control unit 104 is connected to the X-ray generation unit102, the X-ray irradiation switch 103, and the imaging control device107. The X-ray control unit 104 controls the start and end of X-rayirradiation, and transmits imaging execution conditions and positioninformation. Further, the X-ray control unit 104 receives imagingconditions and position information from the imaging control device 107,and notifies the X-ray generation unit 102 of the imaging conditions andthe position information.

The imaging table 105 is a support on which an object is placed. Themovement mechanism 1061 of the X-ray detector, which moves the X-raydetector 106 in a direction along the top of the table, is providedimmediately below the top.

The X-ray detector 106 includes an X-ray sensor having a plurality ofphotoelectric conversion elements arranged in a matrix. The X-raydetector 106 detects X-rays transmitted through the object, and convertsthe X-rays into X-ray image data. A discrete two-dimensional planararray of the plurality of photoelectric conversion elements defines anX-ray detection region and an X-ray detection surface. The X-raydetection surface extends in a direction along a surface of the X-raydetector 106, and is desirably substantially parallel to an uppersurface. The X-ray detector 106 is arranged substantially in parallel tothe top of the imaging table. In addition, the X-ray detector movessubstantially in parallel to the top, and therefore the X-ray detector106 moves along the X-ray detection surface. Here, “substantially” meansthat complete parallelism is not required for imaging and, for example,an error of about several degrees is tolerable.

The X-ray detector 106 is further connected to the imaging controldevice 107, and transmits the X-ray image data to the imaging controldevice 107 together with imaging execution information such as the scanarea and the binning size and position information such as the X-raydetector moving distance. Further, the X-ray detector 106 receivesdefault position information from the imaging control device 107, andperforms an imaging preparation process. The transmission of the X-rayimage data and the imaging execution and position information isperformed by using wired communication via a cable connected to theimaging control device 107 or by using wireless communication. Theimaging control device 107 may be configured to receive positioninformation on the X-ray detector 106 from the X-ray control unit 104via the movement mechanism control unit 1063.

The imaging control device 107 is a control device that totally controlsthe X-ray imaging system. The imaging control device 107 controls X-rayimaging with a combination of the X-ray control unit 104 and the X-raydetector 106, a reconstruction process using the X-ray image data, imageprocessing such as tone conversion processing to be performed on theX-ray image data, an execution of an examination including X-rayimaging, input and output to and from the operation unit 108 and thedisplay unit 109, transmission and reception to and from an externaldevice via a network 113, and other operations. The imaging controldevice 107 is constituted by an image processing unit 110, a controlunit 111, and a communication circuit 112.

The imaging control device 107 executes a method for controllingtomosynthesis imaging for obtaining a tomographic image from projectedimages obtained by irradiating an object with X-rays from a plurality ofdifferent angles by using an X-ray generation unit and an X-raydetection unit.

The imaging control device 107 is connected to the X-ray control unit104 and the X-ray detector 106. The imaging control device 107 acquiresprojected images obtained through X-ray imaging and position informationon the X-ray detector 106 and the X-ray generation unit 102 when theprojected images are obtained, and reconstructs a tomosynthesis image.The image obtained by reconstruction is displayed on the display unit109.

Additionally, the imaging control device 107 is connected to an HIS/RIS114, a PACS 115, a viewer 116, and a printer 117 via the network 113.The HIS/RIS 114 is a hospital/radiology information management systemfor managing information in the radiology department, such as patientinformation and examination request information. The PACS 115 is animage management server whose main purpose is to save images. The viewer116 is connected to the PACS 115, and a high-definition monitor ismainly used for visual inspection and detailed post-processing of animage obtained by imaging using the X-ray imaging system 101, and fordiagnostic operations. The printer 117 prints and outputs the X-rayimage data or tomosynthesis image data.

The image processing unit 110 performs image processing, such as toneconversion processing and noise reduction processing, on the receivedX-ray image data. Further, the image processing unit 110 performs areconstruction process using the X-ray image data and the positioninformation to reconstruct a tomosynthesis image. An image reconstructedfrom projected images obtained through tomosynthesis imaging is referredto as a tomosynthesis image in particular. A tomosynthesis imageaccording to one embodiment is a representation of three-dimensionalvolume data based on a plurality of projected images.

The control unit 111 performs control for the execution of anexamination and the execution of imaging, or saves/reads information onthe execution of a suspended examination or a completed examination orX-ray image data. Further, the control unit 111 determines the situationin which interruption of imaging is occurring on the basis of thenotified position information, and determines the availability of theexecution of reconstruction and the availability of the display of anoblique cross section. Further, the control unit 111 calculates validframes of a tomosynthesis image on the basis of the notified positioninformation.

The communication circuit 112 transmits a variety of driving conditionssuch as an accumulation period of time, a binning condition, and a framerate, in addition to an X-ray irradiation preparation request and anX-ray irradiation preparation cancellation request, to the X-ray controlunit 104 and the X-ray detector 106 via a communication I/F. Further,the communication circuit 112 receives X-ray image data, imagingexecution information, and position information from the X-ray controlunit 104 and the X-ray detector 106. Further, the communication circuit112 receives examination request information, transmits examinationexecution information, and outputs the X-ray image data or tomosynthesisimage data via the network 113.

The operation unit 108 is an input interface that accepts an operationperformed by an operator. The input interface of the operation unit 108may be any interface having input capabilities, such as a keyboard, amouse, or a multi-touch monitor. The operation unit 108 transmits inputinformation to the imaging control device 107 in accordance with theoperation. Further, the operation unit 108 receives a request from theimaging control device 107, and switches the display of the inputinterface.

The display unit 109 is an output interface on which a user interface ofcontrol software for X-ray imaging is displayed. The display unit 109may be any interface having display capabilities, such as a separatemonitor or a monitor incorporated in an X-ray imaging apparatus. Aplurality of monitors on which captured images are displayed may beconnected to a single imaging control device 107, and a captured imageand a previous image may be displayed as previews on different monitors.In this case, the display unit 109 judges on which monitor and whichimage is displayed in accordance with a notification from the imagingcontrol device 107.

The image processing unit 110 further generates a two-dimensionaltomographic image from the volume data, if necessary. Examples of thegenerated two-dimensional tomographic image include a tomographic image(first two-dimensional tomographic image) in the direction along thedetection surface. Referring to the configuration of the imaging systemillustrated in FIG. 1, this tomographic image corresponds to a coronalimage of the object. A two-dimensional tomographic image in thedirection along the detection surface (referred to as a firsttwo-dimensional tomographic image) is often used since an obtainedtomographic image can at least have sufficient image quality, whichdepends on the limitations on the irradiation angle in tomosynthesisimaging.

In addition, the image processing unit 110 is also capable of generatinga two-dimensional tomographic image intersecting the detection surface(second two-dimensional tomographic image). For example, the imageprocessing unit 110 is capable of generating a so-called oblique imagethat is a tomographic image having a certain inclination to thedirection of the axis of the body of the object, that is, the movementdirection of the X-ray generation unit 102 and the X-ray detector 106.Needless to say, it is possible to generate any other two-dimensionaltomographic image intersecting the detection surface. For example,referring to the imaging system illustrated in FIG. 1, sagittal imagesor axial images can be generated. In the case of tomosynthesis imagingin which the X-ray generation unit 102 and the X-ray detector 106 aremoved along the axis of the body of the object, it can be conceived interms of image quality that an oblique image is generated whereas nosagittal image or axial image is generated. In the case of tomosynthesisimaging in which the X-ray generation unit 102 and the X-ray detector106 are two-dimensionally moved along the top of the imaging table 105,a sagittal image or an axial image may be generated.

In another embodiment, a set of two-dimensional tomographic imagesalong, more desirably, parallel to, the detection surface of the X-raydetector 106 may be directly reconstructed from a sequence of projectedimages, and may be handled as a tomosynthesis image. In this case, aprocess for directly reconstructing, for example, each of oblique,sagittal, and axial images from projected images is executed.

The communication circuit 112 transmits driving conditions for the X-raydetector 106 to the X-ray detector 106, and receives from the X-raydetector 106 a sequence of projected images to be used for thereconstruction process based on projected images described above.Accordingly, the imaging control device 107 can obtain projected imagesto be used for a reconstruction process.

In addition, the communication circuit 112 receives from the X-raycontrol unit 104 position information on the X-ray generation unit 102and the X-ray detector 106 at the timings when the respective projectedimages are captured. In this regard, the communication circuit 112functions as a unit for acquiring projected images and positioninformation. Based on the sequence of projected images and the positioninformation, the image processing unit 110 performs a reconstructionprocess. The position information includes, for example, information onthe direction in which the X-ray generation unit 102 performs X-rayirradiation to the X-ray detector 106.

Here, the desired tomographic image may not be obtained due to theinterruption of the imaging or the limitations on the movement mechanism1061 or the movement mechanism of the column 1062 or depending onconditions such as the imaging interval for projected images or thesetting of the irradiation angle or the range of the irradiationdirection of the X-ray generation unit 102.

Accordingly, the control unit 111 performs display control to impose alimitation on a second two-dimensional tomographic image to bedisplayed, by using the information on the irradiation direction of theX-ray generation unit 102 within the position information obtained fromthe communication circuit 112. For example, projected images have beenobtained in the irradiation direction from −30 degrees to +10 degrees.In this case, a limitation is imposed such that an oblique image havingan intersection angle up to ±10 degrees to the detection surface of theX-ray detector 106 or the top of the imaging table 105 is displayed,whereas an oblique image having an intersection angle larger than +10degrees or an intersection angle smaller than −10 degrees is notdisplayed. It is a matter of course that an oblique image having anintersection angle up to ±5 degrees may be a target to be displayed.Further, an oblique image may be displayed with an intersection angle inthe range from −30° to +10°. In another example, projected images havebeen obtained with irradiation angles in the range from −20 degrees to+20 degrees. In this case, a limitation is imposed such that an obliqueimage having an intersection angle up to ±20 degrees to the detectionsurface of the X-ray detector 106 or the top of the imaging table 105 isdisplayed, whereas an oblique image having an intersection angle largerthan +20 degrees or an intersection angle smaller than −20 degrees isnot displayed.

In the way described above, a process for specifying the range of thedisplay target on the basis of the range of the irradiation direction,causing a second two-dimensional tomographic image within the specifiedrange of the display target, and removing a second two-dimensionaltomographic image outside the range from the display target is executed.This enables a two-dimensional tomographic image of a guaranteedsufficient quality to be displayed, and can reduce the probability offalse diagnosis.

In another example, in the case of irradiation over a range from −30degrees to 30 degrees, the display of oblique images is prohibited ifonly projected images up to −5 degrees have been obtained. In stillanother example, in the case of similar irradiation conditions, thedisplay of oblique images is also uniformly prohibited if only projectedimages over a range from −30 degrees to 10 degrees are successfullyobtained due to circumstances such as interruption of the imaging. Inthe manner described above, if it is determined that projected imagessatisfying the desired irradiation conditions are not successfullyobtained, a uniform limitation on the display of oblique images canensure higher image quality.

In still another example, if the irradiation interval for projectedimages is 0.5 degrees, oblique images are also controlled not to bedisplayed at intervals less than 0.5 degrees, and, if the irradiationinterval is 0.1 degrees, oblique images are also controlled not to bedisplayed at intervals less than 0.1 degrees. In the manner describedabove, a limitation on the display interval of oblique images by usinginformation on X-ray irradiation directions for the respective projectedimages can ensure the quality of the oblique images to be displayed.

In addition, such generation and display of coronal images or obliqueimages are performed within a modality, in particular, by the imagingcontrol device 107 that controls tomosynthesis imaging. Accordingly,whether or not tomosynthesis imaging is appropriate can be checkedbefore transmission to the PACS 115 and the like, enabling animprovement in the efficiency of medical diagnosis.

Here, a system configuration related to tomosynthesis imaging isillustrated using FIG. 2. The X-ray generation unit 102 is fixed to thecolumn 1062 which is inclinable. During the collection of projectedimage data, the X-ray generation unit 102 and the X-ray detector 106move in horizontally opposite directions, with respect to, as a center,a position at which the imaging table 105 and the column 1062 areperpendicular to each other before the start of irradiation, by a presetdistance in a direction (horizontal direction) along the imaging table105 and the detection surface. In this case, the irradiation range ofthe X-ray generation unit 102 is set so as to be included in thedetection region of the X-ray detector 106. Along with the start ofirradiation, the X-ray generation unit 102 and the X-ray detector 106collect projected image data on which the reconstruction process isbased and acquires position information while moving toward the center.The tomosynthesis image described above is generated based on theprojected image data obtained by imaging in the way described above.

The imaging control device 107 or the X-ray control unit 104 sets therange of the irradiation direction or the irradiation interval of theX-ray generation unit 102. In this embodiment, the column 1062 isconfigured to allow the X-ray generation unit 102 to move on an arc,where the position at which the column 1062 is vertical is defined as a0-degree position and a θ direction is plotted in the left-to-rightdirection in FIG. 2. In addition to this, setting information indicatingplus minus θ degrees is input to the movement mechanism control unit1063 from the imaging control device 107 or the X-ray control unit 104,and the column 1062 causes the X-ray generation unit 102 to move so thatthe initial position before the imaging is minus θ degrees. When theX-ray generation unit 102 is at a position of θ° with respect to theupright direction of the column 1062 (the vertical direction), θ° isreferred to as an irradiation angle. Furthermore, a direction connectingthe focal point of the X-ray generation unit 102 and the center positionof the X-ray detector 106 at this time is referred to as an X-rayirradiation direction. The angle defined by the X-ray irradiationdirection with respect to the vertical direction is θ° in the conditionwhere an isocenter for tomosynthesis imaging is fixed. Thus, in thefollowing exemplary embodiment, the irradiation angle and theirradiation direction are used with similar meanings.

In FIG. 2, the X-ray generation unit 102 moves from left to right. Inaccordance with this setting information, the movement mechanism 1061allows the X-ray detector 106 to move. The range of the irradiationdirection is not limited to the definition described above, and, forexample, a position of −90 degrees in the example described above may beused as a reference. As an alternative, the range of the irradiationdirection of the X-ray generation unit 102 may be set using a parameterother than the angle. For example, as in FIG. 2, the distance over whichthe center position of the column 1062 or the X-ray generation unit 102is displaced from the state where the column 1062 is upright may be usedas setting information. Setting information is converted into themovement mechanism 1061 or the column 1062 or a control value by theX-ray control unit 104 or the movement mechanism control unit 1063, andis output to a driving mechanism for these components, such as a motor,so that the driving mechanism allows the X-ray generation unit 102 andthe X-ray detector 106 to move.

The imaging interval is a parameter indicating an interval at whichprojected images are captured, and has a value defined by the intervalof the irradiation angle, for example. Alternatively, the imaginginterval can be defined by a displacement of the X-ray generation unit102 in the horizontal direction with respect to the position at whichthe column 1062 is upright. The imaging interval is not necessarily anequal interval, and is decided on as necessary. For example, in the caseof imaging with an irradiation angle of ±30 degrees, the imaginginterval is decided on by setting the number of imaging sessions. In thecase of tomosynthesis imaging in the step-and-shoot mode, the movementmechanism control unit 1063 causes the movement mechanism 1061 and thecolumn 1062 to move by a control amount corresponding to the interval ofthe irradiation angle, and the X-ray control unit 104 instructs theX-ray generation unit 102 to emit X-rays at the timing when themovements are stopped. After the X-ray irradiation is completed, themovement mechanism control unit 1063 again causes the movement mechanism1061 and the column 1062 to move by a control amount defined by theparameter of the imaging interval. In the case of tomosynthesis imagingin the continuous mode, X-rays are emitted during the movement. Themovement mechanism control unit 1063 continuously monitors thepositions, and the X-ray control unit 104 starts X-ray irradiation atthe timing when an X-ray irradiation position (imaging position) definedby the imaging interval is reached.

FIG. 3 illustrates the details of the position information obtainedduring the collection of projected image data. As a method for movingthe X-ray generation unit 102, either a method in which the column 1062horizontally moves or a method in which the column 1062 is inclined inits portion in contact with a foundation 202 may be used.

Here, the details of the position information are illustrated using FIG.3. Here, the angle at which the imaging table 105, the X-ray detector106, and the column 1062 to which an X-ray source 201 is fixed areperpendicular is defined as 0°. (I do not have a good explanation forthis; the absolute value of the angle increases like ±1, 2, . . . asinclination increases in opposite directions from) 0°. Further, aposition at which the X-ray detector 106, the X-ray source 201, and theposition of the isocenter are aligned in series with a positionperpendicular to the imaging table 105 is defined as a center positionat which the moving distance is 0. (The absolute value of the movingdistance increases like ±1, 2, . . . in accordance with movements inopposite directions from the center position). The isocenter is in atomographic position at which the clearest image is generated among aplurality of frames of a tomosynthesis image created by reconstruction.The respective moving distances of the X-ray source 201, the X-raydetector 106, and the imaging table 105 on which the object is placedare controlled so that the isocenter is always located on a straightline connecting the focal point position of the X-ray source 201 and thedetection region center position of the X-ray detector 106 during thecapture of projected images. The isocenter-to-table-top distance(hereinafter, referred to the fulcrum) is the distance from theisocenter at the center position to the topmost of the imaging table105. A specific value is used for each imaging session. The fulcrum isset as one of the default imaging conditions included in imagingtechnique information. In addition, a temporary change to the settingsor a change to the default settings can be made by input to theoperation unit 108 during the execution of an examination. The X-raycontrol unit 104 controls the operation of the X-ray generation unit 102by referring to the fulcrum received from the imaging control device107. Thereafter, at the completion of irradiation for projected images,the X-ray control unit 104 receives the input of fulcrum as a piece ofposition information, and transmits the fulcrum to the imaging controldevice 107. The fulcrum is used for the reconstruction process based onthe FBP (Filtered Back Projection) algorithm and the shift-and-addalgorithm. The fulcrum is also used for the calculation of theX-ray-source-to-object distance. The imaging angle is the inclination ofthe X-ray source 201 when the center position is 0°. A maximum imagingangle is set as one of the default imaging conditions included inimaging technique information. In addition, a temporary change to thesettings or a change to the default settings can be made by input to theoperation unit 108 during the execution of an examination. In a singleimaging session, the inclination is successively changed from themaximum imaging angle in the negative direction to the maximum imagingangle in the positive direction through the center position. Thepositive and negative directions in which the inclination is changed maybe reversed. As the imaging angle, an imaging angle obtained when imagedata is read is acquired for each of a plurality of consecutive X-rayimage frames of projected images. At the completion of irradiation forprojected images, the X-ray control unit 104 receives the input of theimaging angle as a piece of position information, and transmits theimaging angle to the imaging control device 107. An imaging angle pitchthat is changed for each read of image data is decided on by dividingthe amount by which the angle is changed in a single imaging session bythe number of frames scheduled to be captured. The imaging angle is usedfor the reconstruction process based on the FBP (Filtered BackProjection) algorithm and the shift-and-add algorithm. The imaging angleis also used for the determination of an imaging state by an imaginginterruption determination unit 401. In addition, the imaging angle isfurther used for limiting the designation of the angle during thedisplay of a reconstruction oblique cross section. The X-ray sourcemoving distance is a distance through which the X-ray source 201 movesin a direction parallel to the imaging table 105 with respect to thecenter position. The X-ray source 201 moves to the right or left fromthe center position in synchronization with the X-ray detector 106, andis inclined at an angle that allows the isocenter to be located on astraight line connecting the focal point position of the X-ray source201 and the detection region center position of the X-ray detector 106to meet the imaging angle corresponding to the setting. Accordingly, theX-ray source moving distance is decided on in synchronization with thesetting of the imaging angle. As the X-ray source moving distance, anX-ray source moving distance obtained when image data is read isacquired for each of a plurality of consecutive X-ray image frames ofprojected images. At the completion of irradiation for projected images,the X-ray control unit 104 receives the input of an X-ray source movingdistance for each X-ray image frame as a piece of position information,and transmits the X-ray source moving distance to the imaging controldevice 107. The X-ray source moving distance is used for thereconstruction process based on the FBP (Filtered Back Projection)algorithm and the shift-and-add algorithm. The X-ray detector movingdistance is a distance through which the X-ray detector 106 moves in adirection parallel to the imaging table 105 with respect to the centerposition. The X-ray detector 106 moves to the right or left from thecenter position in a direction opposite to that of the X-ray source 201in synchronization with the X-ray source 201, and moves so that theisocenter is located on a straight line connecting the focal pointposition of the X-ray source 201 and the detection region centerposition of the X-ray detector 106 to meet the imaging anglecorresponding to the setting. Accordingly, similarly to the X-ray sourcemoving distance, the X-ray detector moving distance is also decided onin synchronization with the setting of the imaging angle. As the X-raydetector moving distance, an X-ray detector moving distance obtainedwhen image data is read is acquired for each of a plurality ofconsecutive X-ray image frames of projected images. At the completion ofirradiation for projected images, the X-ray control unit 104 receivesthe input of an X-ray detector moving distance for each X-ray imageframe as a piece of position information, and transmits the X-raydetector moving distance to the imaging control device 107. The X-raydetector moving distance is used for the reconstruction process based onthe FBP (Filtered Back Projection) algorithm and the shift-and-addalgorithm. An X-ray-source-to-X-ray-detector distance is a distance fromthe X-ray source 201 at the center position to the topmost of the X-raydetector 106. The X-ray-source-to-X-ray-detector distance has a specificvalue for each imaging apparatus. The X-ray-source-to-X-ray-detectordistance is used for the calculation of the X-ray-source-to-objectdistance. A table-top-to-X-ray-detector distance is a distance from thetopmost of the imaging table 105 at the center position to the topmostof the X-ray detector 106. The table-top-to-X-ray-detector distance hasa specific value for each imaging apparatus. Thetable-top-to-X-ray-detector distance is used for the calculation of anX-ray-source-to-object distance. The X-ray-source-to-object distance isa distance from the X-ray source 201 at the center position to theobject with respect to the isocenter. The X-ray-source-to-objectdistance has a specific value for each imaging session depending on thefulcrum set for each imaging session. More specifically, theX-ray-source-to-object distance is calculated by an imaging control unit405 in accordance with the equation below using theX-ray-source-to-X-ray-detector distance, fulcrum, andtable-top-to-X-ray-detector distance included in the positioninformation received by the imaging control device 107 at the completionof irradiation for projected images.X-ray-source-object distance=X-ray-source-to-X-ray-detectordistance−(fulcrum+table-top-to-X-ray-detector distance)

The X-ray-source-object distance is used for the reconstruction processbased on algorithms such as the FBP (Filtered Back Projection) algorithmand the shift-and-add algorithm.

The parameters described above are used as position information on theX-ray generation unit 102 and the X-ray detector 106. Among the piecesof position information, the isocenter position, thetable-top-to-X-ray-detector distance, and the fulcrum have common valuesfor the imaging system or in a single imaging session, whereas the otherpieces of position information are different for the capture of eachprojected image. Accordingly, a set of pieces of position informationcommon for a single imaging session and position information differentfor each projected image is output from the X-ray control unit 104 tothe imaging control device 107 via the movement mechanism control unit1063.

FIG. 4 illustrates a detailed configuration of the control unit 111related to the X-ray imaging system 101 in the present invention. Thecontrol unit 111 includes the imaging interruption determination unit401, an imaging technique information storage unit 402, an examinationinformation storage unit 403, an imaging control unit 405, a conditionsetting unit 4051, an examination control unit 406, a display controlunit 4070, an input detection unit 4071, an image output control unit409, and a progress level measuring unit 4011.

The imaging technique information storage unit 402 saves, updates,deletes, and searches for imaging technique information. The imagingtechnique information illustrated here includes items that can be setfor each imaging technique and that cover from the execution of imagingto post-processing and image output settings, such as information foridentifying an imaging technique such as the part to be imaged and theimaging direction, imaging conditions, image processing parameters,reconstruction parameters, storage transfer settings, and printingsettings. The imaging technique information storage unit 402 isconstituted by a database. The examination information storage unit 403registers, updates, deletes, and searches for examination information ofexamination information. The examination information storage unit 403 isconstituted by a database.

The imaging control unit 405 transmits and receives data of imagingavailability, imaging execution conditions, and position information toand from the X-ray generation unit 102 and the X-ray detector 106 viathe communication circuit 112. Further, the imaging control unit 405performs control of the overall flow of a single X-ray imaging sessionand the overall flow of the execution of a reconstruction process, suchas control for the execution of a reconstruction process and the storageof X-ray image data.

The condition setting unit 4051 sets an imaging condition in accordancewith, for example, an operation input from the operation unit 108. Thecondition setting unit 4051 is a setting unit that extracts imagingconditions from the imaging technique information obtained from theimaging technique information storage unit 402 and that transmits theimaging conditions as imaging parameters to the respective units such asthe imaging control unit 405, the image processing unit 110, the X-raydetector 106, the X-ray generation unit 102, and the movement mechanismcontrol unit 1063. The term imaging parameters, as used herein, is usedto include, for example, the number of projected images captured, theimaging interval for projected images, information on a range of X-rayirradiation positions (±θ), the number of coronal image first secondarytomographic images (coronal images) created, the creation pitch, otherimage processing parameters, and drive parameters for the X-ray detector106.

The examination control unit 406 performs control of the overall flow ofthe execution of an examination, such as control of theupdate/registration of patient information,examination-scheduled-to-be-conducted information, and imaging techniqueinformation, control of screen transitions, storage of tomosynthesisimage data, and a process for adding a tomosynthesis image. The termexamination refers to a concept that encompasses a plurality of units ofimaging, and common information is processed for a transition betweenimaging sessions and a plurality of imaging sessions included in oneunit of examination.

The input detection unit 407 accepts and interprets an operation inputfrom the operation unit 108. The display control unit 4070 performs theoverall display control of the display unit 109 in response to outputinstructions notified by the examination control unit 406, such as ascreen transition. For example, the display control unit 4070 performsdisplay control of a projected image or a tomosynthesis image, a processfor changing the display of a GUI (Graphical User Interface) inaccordance with the operation input to the operation unit 108, and soforth.

The image output control unit 409 determines image output availabilityof an image included in the received examination information, andinstructs the communication circuit 112 to output the image to an outputdevice 410. The output device 410 corresponds to, for example, the PACS115, the viewer 116, or the printer 117.

The imaging interruption determination unit 401 determines whether ornot the imaging has been interrupted, by using the position informationnotified from the X-ray control unit 104. If the imaging is interrupted,position information not corresponding to a predetermined range ofirradiation positions is obtained or the number of projected images isinsufficient to meet a specified amount. Accordingly, the imaginginterruption determination unit receives, as input, information on apreset number of projected images captured, information on the range ofirradiation positions, position information obtained as a result ofimaging, information on projected images, and other information, anddetermines whether or not the tomosynthesis imaging has beeninterrupted.

An example of the interruption determination method is as follows. In acase where the number of projected images captured has been set by thecondition setting unit 4051, if the number of projected images obtainedthrough the communication circuit 112 is less than that value, theimaging interruption determination unit 401 determines that the imaginghas been interrupted. If both numbers match, the imaging interruptiondetermination unit 401 determines that the imaging has been completed.

In another example, it is determined that the imaging has beeninterrupted if the number of elements of position information includedin the set of pieces of position information obtained from the X-raycontrol unit 104 is smaller than a predetermined number of capturedimages, and it is determined that the imaging has been completed if thenumber of elements is equal to the number of captured images. If thenumber of elements of position information is larger than the number ofcaptured images, it can be determined that an error has occurred.Alternatively, if at least one of the number of pieces of positioninformation and the number of projected images is smaller than aprescribed number of captured images, it is determined that the imaginghas been interrupted. If both numbers match the number of capturedimages, it is determined that the imaging has been completed withoutinterruption. Such an example is also provided.

In another example, in a case where the range of irradiation positionsis set to ±θ, it is determined that the imaging has been interrupted ifthe position information obtained through the communication circuit 112ranges from −θθ to +θ′ (<θ), and it is determined that the imaging hasbeen completed if data in the range from −θ to +θ has been obtained. Inthis case, the actually set range does not necessarily exactly match arange of position information acquired in actuality. Thus, for example,any digits in the difference after the decimal place are ignored and itis determined that an interruption has occurred.

Alternatively, the X-ray control unit 104 may be configured to outputnotifications of the start, interruption, and completion of imaging, andthe output may be received by the communication circuit 112 andinterpreted by the interruption determination unit 401 to determine thatan interruption has occurred.

Alternatively, there is also considered a case where the pieces ofposition information described above are not used directly fordetermination. For example, during imaging, the communication circuit112 regularly receives the progress of capturing projected images fromthe X-ray control device 104. If the X-ray control device 104 notifiesthe imaging control device 107 of the completion of the imaging beforethe progress reaches 100%, it is determined that an interruption hasoccurred. If there is a notification indicating that the progress hasreached 100%, it is determined that the imaging has been completedwithout interruption. The progress is obtained in the X-ray controldevice 104 by, for example, dividing the number of times irradiation hasbeen provided by a specified number of times of irradiation. Instead ofthe progress, the value of the number of times imaging has beenperformed (the number of times of irradiation) can be directly handledas information indicating the degree of progress.

Alternatively, such a degree of progress can be obtained within thecontrol unit 111. In such an embodiment, the control unit 111 includesthe progress level measuring unit 4011. The progress level measuringunit 4011 measures a level of progress of imaging by using settinginformation, such as the number of projected images captured and theinformation on the range of irradiation positions, and executioninformation, such as the number of projected images that have beencaptured and the set of pieces of position information. After thecompletion of the imaging, the progress level measuring unit 4011identifies a degree of progress indicating a degree to which the captureof projected images has been completed, or a level of progress ofimaging, by using information such as the set of pieces of positioninformation.

The display control unit 4070 limits the display of oblique images orsecond two-dimensional tomographic images by using the information onthe degree of progress of the imaging. For example, the display ofoblique images is limited in accordance with the degree of progress insuch a manner that, if it is determined that the imaging has beeninterrupted when the degree of progress is 60%, oblique images havingintersection angles up to 5 degrees to the detection surface aredisplayed, and oblique images having intersection angles up to 15degrees are displayed if an interruption has occurred when the degree ofprogress is 80%. The relationship between the degree of progress and thedegree of limitation of display can be experimentally determined.

In addition, for example, the display control unit 4070 imposes alimitation so that no two-dimensional tomographic image (secondtwo-dimensional tomographic image) intersecting the detection surface isdisplayed if the imaging interruption determination unit 401 determinesthat an interruption has occurred and if the degree of progress isgreater than or equal to 50% and less than 100%. On the other hand,since the degree of progress is greater than or equal to 50%, theembodiment in FIG. 2 described above allows projected image dataobtained by irradiation from the respective positions in the range of atleast −θ° to 0° to have been obtained. Thus, a two-dimensionaltomographic image (coronal image) along the detection surface isdisplayed because the quality can be guaranteed. This threshold valuemay be set as desired by the display control unit 4070 or may beexperimentally determined in accordance with the progress andinformation on irradiation positions. If the degree of progress is lessthan 50%, the display of both a first tomographic image and a secondtomographic image is limited. In this case, the imaging control unit 405additionally performs control to prohibit the reconstruction process fora tomosynthesis image, which is performed by the image processing unit110, to lessen the processing load. In this case, furthermore, the imageoutput control unit 409 handles imaging data of the relevant projectedimage group as reject data, and limits the output of such data to theoutput device 410, which can prevent unwanted image data from beingoutput.

The hardware example configuration of the imaging control deviceaccording to the embodiment will be described with reference to FIG. 5.The control unit 111 includes a CPU 501, a ROM 502, a RAM 503, an HDD504, an input detection unit 505, a communication I/F 506, a graphicsboard 507, and a display driver 508. These components are connected toone another via a bus such as a data bus. The CPU 501 is configured toperform the overall control of the control unit 111, and executes aninstruction program stored in the ROM 502 to execute control. Theprogram is executed by the CPU 501 to cause the control unit 111 toexert the functions of the imaging interruption determination unit 401,the progress level measuring unit 4011, the imaging techniqueinformation storage unit 402, the examination information storage unit403, the imaging control unit 405, the condition setting unit 4051, theexamination control unit 406, the display control unit 4070, the inputdetection unit 4071, and the image output control unit 409. Further, theprogram is a program for executing processes illustrated in FIG. 6, FIG.7, and FIG. 13 described below.

Further, the CPU 501 performs input/output control for the display unit109 via the display driver 508, and input/output control for theoperation unit 108 via the input detection unit 505. The RAM 503 isconfigured to reserve a working storage area when the CPU performscontrol in accordance with an instruction program. The HDD 504 is anauxiliary storage device that saves various kinds of data such as X-rayimage data. The communication I/F 506 is a communication interfaceconstituting the communication circuit 112, and transmits and receivesdata between the control unit 111 and each of the X-ray control unit104, the X-ray detector 106, and the network 113. The graphics board 507is configured to constitute the image processing unit 110, and performsimage processing and a reconstruction process using a GPU.

Subsequently, an example of the flow from the start to the end of atypical tomosynthesis imaging examination in the present invention isillustrated using FIG. 6.

In step S601, patient information is created prior to the start of theexamination. The patient information illustrated here includes all thepieces of information for identifying a patient, such as the patient'sname, patient ID, age, date of birth, gender, height, weight, andpregnancy state.

In step S601, the display unit 109 displays a patient information inputscreen 801. When an instruction for confirming the patient informationis given, the operation unit 108 transmits a patient informationconfirmation notification including the patient information to the inputdetection unit 4071. Upon receipt of the patient informationconfirmation notification, the input detection unit 4071 transmits thepatient information confirmation notification to the examination controlunit 406. Upon receipt of the patient information confirmationnotification, the examination control unit 406 newly generatesexamination-scheduled-to-be-conducted information. Theexamination-scheduled-to-be-conducted information illustrated hereincludes the patient information described above, examinationinformation including all the items for identifying an examination, suchas examination ID and examination date and time, and imaging techniqueinformation including all the pieces of information for identifying animaging technique, such as the part to be imaged. Then, the examinationcontrol unit 406 inputs the patient information included in the patientinformation confirmation notification to theexamination-scheduled-to-be-conducted information. Thereafter, theexamination control unit 406 transmits a notification of a request toobtain all the registered imaging technique information to the imagingtechnique information storage unit 402. Upon receipt of the notificationof the request to obtain all the imaging technique information, theimaging technique information storage unit 402 acquires all theregistered imaging technique information, and transmits the acquiredimaging technique information to the examination control unit 406. Uponreceipt of the imaging technique information, the examination controlunit 406 transmits an imaging technique selection screen transitionnotification together with the imaging technique information to thedisplay control unit 4070. Upon receipt of the imaging techniqueselection screen transition notification, the display control unit 4070transmits the imaging technique selection screen transition notificationto the display unit 109 for display. Upon receipt of the imagingtechnique selection screen transition notification, the display unit 109displays an imaging technique selection screen 901. The display unit 109displays all the pieces of received imaging technique information on theimaging technique selection screen 901.

Then, in step S602, examination information is created. The creation ofexamination information illustrated here includes the selection of ascheduled imaging technique. When an instruction for starting theexamination is given, the operation unit 108 transmits an examinationinformation confirmation notification including the examinationinformation and the selected scheduled imaging technique to the inputdetection unit 4071. Upon receipt of the examination informationconfirmation notification, the input detection unit 4071 transmits theexamination information confirmation notification to the examinationcontrol unit 406. Upon receipt of the examination informationconfirmation notification, the examination control unit 406 inputs theexamination information and the scheduled imaging technique, which areincluded in the examination information confirmation notification, tothe examination execution information generated at the time when thepatient information is confirmed.

The flow of manually creating patient information, examinationinformation, and a scheduled imaging technique is illustrated in stepsS601 to S602, but is not limited thereto. Selecting work listinformation acquired from the HIS/RIS 114 enables patient information,examination information, and a scheduled imaging technique to be createdat once. In this case, step S601 is omitted. When an instruction forstarting the examination is given, the operation unit 108 transmits anexamination information confirmation notification including patientinformation, examination information, and a scheduled imaging technique,which are included in the selected work list information, to the inputdetection unit 4071. The subsequent flow is similar to that describedabove.

Then, in step S603, an examination start process is carried out. Whenthe creation of examination execution information is completed in stepS602, the examination control unit 406 transmits an examination startnotification to the examination information storage unit 403 and thedisplay control unit 4070. The examination start notification includesexamination-scheduled-to-be-conducted information. Upon receipt of theexamination start notification, the examination information storage unit403 registers the examination-scheduled-to-be-conducted information asnew examination information. Then, the examination information storageunit 403 updates the examination status of the registered newexamination information to in progress“. The examination status includesnot started”, in progress“, in suspension”, and “end”. Upon receipt ofthe examination start notification, the display control unit 4070transmits an imaging screen transition notification to the display unit109. The imaging screen transition notification includes theexamination-scheduled-to-be-conducted information. Upon receipt of theimaging screen transition notification, the display unit 109 displays animaging screen 1001. The display unit 109 displays, on the imagingscreen 1001, the patient information, the examination information, andthe imaging technique information included in the received examinationinformation.

In step S604, an imaging technique with which imaging is executed nextis selected from among the scheduled imaging techniques included in thestarted examination information. The selection of an imaging techniqueis selected by pressing an imaging technique display portion 1009displayed on the imaging screen 1001. Upon acceptance of the pressing ofan imaging technique button, the operation unit 108 transmits an imagingtechnique selection notification to the input detection unit 4071. Theimaging technique selection notification includes selected imagingtechnique information. Upon receipt of the imaging technique selectionnotification, the input detection unit 4071 transmits an imagingtechnique selection notification to the examination control unit 406.The display control unit 4070 transmits anunder-preparation-for-irradiation display notification to the displayunit 109. Upon receipt of the under-preparation-for-irradiation displaynotification, the display unit 109 switches the display of a sensorstatus display portion 903 on the imaging screen 1001. Upon receipt ofthe imaging technique selection notification, the examination controlunit 406 transmits an irradiation permission request notification to theimaging control unit 405. The irradiation permission requestnotification includes the selected imaging technique information. Uponreceipt of the irradiation permission request notification, the imagingcontrol unit 405 transmits the irradiation permission requestnotification to the communication circuit 112. Upon receipt of theirradiation permission request notification, the communication circuit112 transmits the irradiation permission request notification to theX-ray control unit 104 and the X-ray detector 106. Upon receipt of theirradiation permission request notification, the X-ray control unit 104notifies the X-ray generation unit 102 of the imaging conditions andposition information included in the imaging technique informationincluded in the irradiation permission request notification. Thereafter,when the setting of conditions for the X-ray generation unit 102 and themovement of the X-ray generation unit 102 to the initial position arecompleted, the X-ray control unit 104 transmits an irradiationpermission notification to the communication circuit 112. Theirradiation permission notification includes imaging techniqueinformation for which irradiation has been permitted. Upon receipt ofthe irradiation permission request notification, the X-ray detector 106moves to the default position in accordance with the default positioninformation included in the imaging technique information included inthe irradiation permission request notification. When X-ray detection isready for use, the X-ray detector 106 transmits an irradiationpermission notification to the communication circuit 112. Upon receiptof the irradiation permission notifications from both the X-ray controlunit 104 and the X-ray detector 106, the communication circuit 112transmits an irradiation permission notification to the imaging controlunit 405. Upon receipt of the irradiation permission notification, theimaging control unit 405 transmits the irradiation permissionnotification to the examination control unit 406. Upon receipt of theirradiation permission notification, the examination control unit 406transmits the irradiation permission notification to the display controlunit 4070. Upon receipt of the irradiation permission notification, thedisplay control unit 4070 transmits an irradiation permission displaynotification to the display unit 109. Upon receipt of the irradiationpermission display notification, the display unit 109 switches thedisplay of the sensor status display portion 903 on the imaging screen1001. Further, the display unit 109 displays an intended-for-imagingthumbnail 1012 in the imaging technique display portion 1009 on theimaging screen 1001. In the way described above, switching the displayof the sensor status display portion 903 and the imaging techniquedisplay portion 1009 allows the viewer to easily identify thatirradiation is available and distinguish the imaging technique for whichan image is to be added in the next irradiation. While the flow ofmanual selection of an imaging technique has been described, the presentinvention also enables automatic selection of an imaging technique atthe timing when the next imaging session is ready to start, such as atthe start of an examination or at the end of irradiation. In this case,at the time when the next imaging session is ready to start, theexamination control unit 406 acquires imaging technique informationwhose status is “imaging not yet started” from among the scheduledimaging technique information included in theexamination-scheduled-to-be-conducted information. The status of theimaging technique information includes “imaging in progress” and“imaging completed” as well as “imaging not yet started”. Theexamination control unit 406 selects the first registered imagingtechnique in the imaging technique information indicating “imaging notyet started”, and transmits an irradiation permission request. Themethod for selecting one imaging technique is not limited thereto. Thiscan save the time taken for an operator to manually select the nextimaging technique each time imaging is performed, and achieve smoothwork flow.

In step S605, the object is placed. The placement of the object isperformed by an operator or a person in charge of the examination. StepS605 may be performed before or after steps S601 to S604.

In step S606, a center position for reconstruction is set. Mainly theoperator or the person in charge of the examination measures the centerposition (hereinafter, the isocenter position) on the basis of theregion of interest of the object, and the isocenter position is inputthrough the operation unit 108. When the input of the isocenter positionis confirmed, the operation unit 108 transmits a center positionconfirmation notification to the input detection unit 4071. The centerposition confirmation notification includes isocenter positioninformation. Upon receipt of the center position confirmationnotification, the input detection unit 4071 transmits the centerposition confirmation notification to the examination control unit 406.Upon receipt of the center position confirmation notification, theexamination control unit 406 transmits the center position confirmationnotification to the imaging control unit 405. Upon receipt of the centerposition confirmation notification, the imaging control unit 405 inputsthe isocenter position information to the position information includedin the currently selected imaging technique information.

In step S607, positioning of the object with fluoroscopy is performed.In particular, since the influence of artifacts on tomosynthesis largelydepends on the direction of X-rays with which the examinee isirradiated, fluoroscopy is used to check the placement of the patient tocheck whether the object has been placed in the correct position. Whenthe X-ray irradiation switch 103 is pressed, the X-ray irradiationswitch 103 transmits an irradiation start request to the X-ray controlunit 104. Upon receipt of the irradiation start request, the X-raycontrol unit 104 transmits an irradiation start instruction to the X-raygeneration unit 102. Upon acceptance of the irradiation startinstruction, the X-ray generation unit 102 starts X-ray irradiation.Thereafter, the X-ray generation unit 102 transmits an irradiation startnotification to the X-ray control unit 104. Upon receipt of theirradiation start notification, the X-ray control unit 104 transmits theirradiation start notification to the imaging control unit 405 via thecommunication circuit 112. Upon receipt of the irradiation startnotification, the imaging control unit 405 transmits the irradiationstart notification to which the currently selected imaging techniqueinformation is added to the examination control unit 406. Upon receiptof the irradiation start notification, the examination control unit 406updates the status of the imaging technique for which irradiation hasbeen started within the imaging technique information included in theexamination-scheduled-to-be-conducted information to “imaging inprogress”. Further, the examination control unit 406 transmits theirradiation start notification to the display control unit 4070. Uponreceipt of the irradiation start notification, the display control unit4070 transmits an irradiation-in-progress display notification to thedisplay unit 109. Upon receipt of the irradiation-in-progress displaynotification, the display unit 109 switches the display of the sensorstatus display portion 903 on the imaging screen 1001. Meanwhile, theX-ray detector 106 detects the emitted X-rays, and converts the X-raysinto X-ray image data. Further, the X-ray detector 106 acquires positioninformation in synchronization with the detection of the X-rays. TheX-ray detector 106 transmits the X-ray image data and the positioninformation to the imaging control unit 405 via the communicationcircuit 112. Upon receipt of the X-ray image data and the positioninformation, the imaging control unit 405 inputs the positioninformation to the currently selected imaging technique. Further, theimaging control unit 405 transmits the X-ray image data to theexamination control unit 406. Upon receipt of the X-ray image data, theexamination control unit 406 transmits the X-ray image data to thedisplay control unit 4070. Upon receipt of the X-ray image data, thedisplay control unit 4070 transmits the X-ray image data to the displayunit 109. Upon receipt of the X-ray image data, the display unit 109displays the X-ray image data in live view in an image display portion1002 on the imaging screen 1001. Thereafter, when the X-ray irradiationswitch 103 is released, the X-ray irradiation switch 103 transmits anirradiation stop request to the X-ray control unit 104. Upon receipt ofthe irradiation stop request, the X-ray control unit 104 transmits anirradiation stop instruction to the X-ray generation unit 102. Uponacceptance of the irradiation stop instruction, the X-ray generationunit 102 stops X-ray irradiation. Thereafter, the X-ray generation unit102 transmits an irradiation end notification and an imaging executioncondition notification to the X-ray control unit 104. The imagingexecution condition notification includes imaging execution conditionsand position information. Upon receipt of the irradiation endnotification and the imaging execution condition notification, the X-raycontrol unit 104 transmits the irradiation end notification and theimaging execution condition notification to the imaging control unit 405via the communication circuit 112. Upon receipt of the irradiation endnotification and the imaging execution condition notification, theimaging control unit 405 transmits the irradiation end notification towhich the currently selected imaging technique information is added andthe imaging execution condition notification to the examination controlunit 406. Upon receipt of the irradiation end notification, theexamination control unit 406 updates the status of the imaging techniquefor which irradiation has been completed within the imaging techniqueinformation included in the examination-scheduled-to-be-conductedinformation to “imaging completed”. Further, upon receipt of theirradiation implementation condition notification, the examinationcontrol unit 406 inputs the irradiation implementation conditions to theimaging technique for which irradiation has been completed within theimaging technique information included in theexamination-scheduled-to-be-conducted information. At the same time, theexamination control unit 406 transmits the irradiation end notificationand the imaging execution condition notification to the display controlunit 4070. Upon receipt of the irradiation end notification and theimaging execution condition notification, the display control unit 4070transmits an irradiation end display notification and the imagingexecution condition notification to the display unit 109. Upon receiptof the irradiation end display notification, the display unit 109switches the display of the sensor status display portion 903 on theimaging screen 1001. Further, upon receipt of and the imaging executioncondition notification, the display unit 109 updates the correspondingdisplay annotation in an image display portion 902. While the case wherethe X-ray generation unit 102 simultaneously transmits an irradiationend notification and an imaging execution condition notification hasbeen described, the present invention is not limited thereto. Anotification of imaging execution conditions may be sent in real timeduring irradiation, or imaging execution conditions may be transmittedafter the end of irradiation at a different timing from the transmissionof an irradiation end notification. Alternatively, imaging executionconditions and position information may be transmitted at differenttimings.

Tomosynthesis imaging may not involve positioning with fluoroscopy. Inthis case, step S607 is omitted.

In step S608, projected images are captured. The process flow for thecapture of projected images is almost similar to that with fluoroscopyin step S607. Note that, in the capture of projected images, uponreceipt of the X-ray image data and the position information, theimaging control unit 405 inputs the position information to thecurrently selected imaging technique and saves the X-ray image data. Inthe present invention, furthermore, upon receipt of an irradiation endnotification for projected images, the imaging control unit 405determines the situation in which interruption of imaging is occurringfrom the position information. The imaging control unit 405 decides onwhether a reconstruction process is available or not or whether thedisplay of an oblique cross section is available or not in accordancewith the situation in which interruption of imaging is occurringobtained as a result of the determination, and notifies the examinationcontrol unit 406 of the result (FIG. 13). This can prevent wastefulexecution of reconstruction and prevent the display of an ineffectivetomosynthesis image if the capture of projected images has beeninterrupted. This can also avoid the risk of false diagnosis by thereference to an oblique cross section with missing information.

In step S609, a reconstruction process is performed. Upon receipt of theX-ray image data of projected images and position information, theimaging control unit 405 transmits a reconstruction start notificationto the display control unit 4070. At the same time, the imaging controlunit 405 transmits a reconstruction request notification to the imageprocessing unit 110. The reconstruction request notification includesthe imaging technique information, the X-ray image data, and theposition information. In this case, in the present invention, theimaging control unit 405 compares the number of frames of the X-rayimage data of the projected images with the number of elements ofposition information. If both numbers are equal, the imaging controlunit 405 transmits the reconstruction request notification as is. Ifthere is a discrepancy between the numbers, the imaging control unit 405performs a correction process to make the numbers match, and thentransmits the reconstruction request notification (FIG. 13). This canalso avoid the risk of failure of the reconstruction process if adiscrepancy occurs between the number of frames of the X-ray image dataand the number of elements of position information due to factors suchas incorrect control of the X-ray generation unit 102 or the X-raydetector 106. Upon receipt of the reconstruction start notification, thedisplay control unit 4070 transmits reconstruction screen display to thedisplay unit 109. Upon receipt of the reconstruction screennotification, the display unit 109 displays a reconstruction screen1101, and displays a progress bar on the image display portion 1002.Meanwhile, upon receipt of the reconstruction request notification, theimage processing unit 110 performs a reconstruction process by usingdefault reconstruction parameters in the imaging technique information,the position information, and the X-ray image data. When thereconstruction process is completed, the image processing unit 110transmits a reconstruction completion notification to the imagingcontrol unit 405. The reconstruction completion notification includesthe generated tomosynthesis image, reconstruction parameters, and imageprocessing parameters. Upon receipt of the reconstruction completionnotification, the imaging control unit 405 transmits the reconstructioncompletion notification to the examination control unit 406.

Upon receipt of a reconstruction confirmation notification, theexamination control unit 406 transmits a reconstruction end notificationto the display control unit 4070. The reconstruction end notificationincludes imaging technique information in which the saved tomosynthesisimage is present. Upon receipt of the reconstruction end notification,the display control unit 4070 transmits an imaging screen displaynotification to the display unit 109. Upon receipt of the imaging screendisplay notification, the display unit 109 shows a transition to theimaging screen 1001. At the same time, the display unit 109 adds acaptured image thumbnail 1011 of the saved tomosynthesis image, anddisplays the captured image thumbnail 1011 as a preview.

In step S610, post-processing for tomosynthesis images is performed. Thepost-processing for tomosynthesis images includes the editing of croppedregions, parallel display (multi-view) of tomosynthesis images, are-imaging process, and a reject process. When all the scheduled imagingtechniques have been completed and the post-processing for tomosynthesisimages has been completed, an examination end instruction is given. Whenan examination end instruction is given, the operation unit 108transmits an examination end request notification to the input detectionunit 4071. Upon receipt of the examination end request notification, theinput detection unit 4071 transmits the examination end requestnotification to the examination control unit 406. Then, in step S611, anexamination termination process is carried out. The examination controlunit 406 transmits an examination end notification to the examinationinformation storage unit 403 and the display control unit 4070. Theexamination end notification includesexamination-scheduled-to-be-conducted information. At the same time, theexamination control unit 406 transmits an image output notification tothe image output control unit 409. The image output notificationincludes examination-scheduled-to-be-conducted information. Upon receiptof the examination end notification, the examination information storageunit 403 searches for and acquires examination-scheduled-to-be-conductedinformation from the registered examination information. Then, theexamination information storage unit 403 updates the examination statusin the acquired examination information to “end”. Upon receipt of theexamination end notification, the display control unit 4070 transmitsthe examination end notification to the display unit 109. Upon receiptof the examination end notification, the display unit 109 shows atransition to the patient information input screen 801. Also when theoperation unit 108 accepts a suspension of the examination, a flowsimilar to that for the termination of the examination is used. Notethat the examination information storage unit 403 updates theexamination status in the acquired examination information to “insuspension”. Then, in step S612, image output is carried out. Uponreceipt of the image output notification, the image output control unit409 performs an image output process for the output device 410 via thecommunication circuit 112.

Here, the flow of an image output process in the present invention willbe illustrated using FIG. 7. First, in step S701, an examinationtermination process is carried out. The examination termination processis similar to that in step S611 in FIG. 6. Then, in step S702, the imageoutput control unit 409 acquires all the imaging techniques whose statusis “imaging completed” from the examination-scheduled-to-be-conductedinformation included in the image output notification, and acquires theimage information at the beginning. Then, in step S703, the image outputcontrol unit 409 checks the reject state of the acquired imageinformation. If the reject state is OFF, the image output control unit409 proceeds to step S704. In step S704, the image output control unit409 transmits an image output request notification to the communicationcircuit 112. The image output request notification includes X-ray imagedata or tomosynthesis image data, and image information. At the sametime, the image output control unit 409 sets the output state of theimage information to ON. Upon receipt of the image output requestnotification, the communication circuit 112 outputs the image data ortomosynthesis image data included in the image output requestnotification to the output device 410. Then, in step S705, the imageoutput control unit 409 checks whether or not an output process has beenperformed on all the pieces of image information acquired in step S702.If the output state of the image information is ON or the reject stateis ON, the image output control unit 409 judges that an output processhas been performed. If there is any image information on which no outputprocess has been performed, the image output control unit 409 returns tostep S702. If an output process has been performed on all the pieces ofimage information, the image output control unit 409 proceeds to stepS706. Then, in step S706, the image output control unit 409 transmits animage output completion notification to the examination control unit406. Thus, the image output process ends.

In the way described above, the image output control unit 409 limits thetransmission of data set as a reject to an external device.

In the following, a description will be given of an example displayscreen displayed on the display unit 109 by the display control unit4070.

An example of the patient information input screen 801 displayed in stepS601 in FIG. 6 will be illustrated with reference to FIG. 8. The patientinformation input screen 801 is a screen on which information on apatient to be subjected to an examination is input. The patientinformation input screen 801 is constituted by a patient informationinput portion 802, a patient information list 803, a patient informationconfirmation instruction portion 804, a patient information displayportion 805, an examination information display portion 806, and anexamination start instruction portion 807. The patient information inputportion 802 is an area in which values of items included in the patientinformation are input or selected. In the patient information list 803,pieces of patient information used for examinations conducted in thepast are displayed in list form. The patient information list 803 hascolumns, each showing one of the items included in the patientinformation. The list has rows, each showing a piece of patientinformation on one patient. When an arbitrary one of the pieces ofpatient information in the list is selected, the selected piece ofpatient information is input to the respective entry portions in thepatient information input portion 802. The patient informationconfirmation instruction portion 804 is a button for confirming thevalues input to the patient information input portion 802 as patientinformation. When the button is pressed, it is checked whether valueshave been input to required input items or whether the values input tothe input items are correct or acceptable. If there is no problem, thevalues are confirmed as patient information. The patient informationdisplay portion 805 is an area in which confirmed patient information isdisplayed. No values are displayed in items until patient information isconfirmed, and, at the time when patient information is confirmed,values are displayed. The examination information display portion 806 isan area in which input examination information is displayed. Theexamination information illustrated here includes information foridentifying an examination, such as an examination ID, an inquiringphysician's name, a radiologist's name, examination description, and afacility name. In addition, an imaging technique selected as intendedfor imaging is also included. Note that at least one or more imagingtechniques are selectable per examination. The examination informationdisplay portion 806 has an area in which items in the examinationinformation are displayed, and an area in which the selected imagingtechnique or imaging techniques are displayed. No values are displayedin the respective items until examination information is input.Likewise, no imaging techniques are displayed until any imagingtechnique is selected. Values and an imaging technique are respectivelydisplayed when examination information is input and at the time when theimaging technique is selected. In addition, a plurality of examinationscan be conducted at once in a single imaging session. In this case, anumber of examination information display portions 806 corresponding tothe number of examinations are displayed side by side. The examinationstart instruction portion 807 is a button for providing an instructionto start an examination. When the button is pressed, it is checkedwhether patient information and examination information have been inputand, in addition, whether one or more imaging techniques have beenselected for each examination. If there is no problem, an examinationstart process is carried out. If there is any examination for which noimaging technique has been selected, the imaging technique selectionscreen 901 is displayed.

Next, an example of the imaging technique selection screen 901 displayedin step S602 in FIG. 6 is illustrated using FIG. 9. The imagingtechnique selection screen 901 is a screen on which an imaging techniqueintended for imaging in an examination to be conducted is selected. Theimaging technique selection screen 901 is constituted by an imagingtechnique display portion 902, imaging technique buttons 903, a patientinformation display portion 904, an examination information displayportion 905, a selected imaging technique button 906, and an examinationstart instruction portion 907. The imaging technique display portion 902is an area in which the imaging techniques saved in the imagingtechnique information storage unit 402 are displayed one by one by usingthe imaging technique buttons 903. The locations where the buttons aredisplayed can be changed as desired. In addition, one page is notsufficient to display all the buttons, the buttons can be displayed overa plurality of pages, in which case the display pages are switched inresponse to an instruction to switch between pages. The imagingtechnique buttons 903 are buttons each displayed for one of the imagingtechniques saved in the imaging technique information storage unit 402.Each imaging technique button shows the name of an imaging technique andthe name of a sensor to be used. When any button is pressed, theselected item is confirmed as intended for imaging in the currentlyselected examination. The patient information display portion 904 is anarea in which confirmed patient information is displayed. Theexamination information display portion 905 is an area in which inputexamination information is displayed. As the selected imaging techniquebutton 906, an imaging technique button 903 selected in the imagingtechnique display portion 902 is displayed. Since one or more imagingtechniques are selectable for each examination, another selected imagingtechnique button 906 is added to the bottom of the examinationinformation display portion 905 each time an imaging technique button isselected. The examination start instruction portion 807 is a button forproviding an instruction to start an examination. When the button ispressed, it is checked whether patient information and examinationinformation have been input and, in addition, whether one or moreimaging techniques have been selected for each examination. If there isno problem, an examination start process is carried out. When anexamination start process is carried out, a transition to the imagingscreen 1001 occurs. If there is any examination for which no imagingtechnique has been selected, the user is prompted to select any imagingtechnique, and no screen transition occurs. The imaging techniqueselection screen 901 having the configuration described above isdisplayed.

Next, an example of the imaging screen 1001 displayed in step S603 inFIG. 6 is illustrated using FIG. 10. The imaging screen 1001 isconstituted by an image display portion 1002, a status display portion1003, a single-view instruction portion 1004, a multi-view instructionportion 1005, a frame-view instruction portion 1006, a patientinformation display portion 1007, an examination information displayportion 1008, an imaging technique display portion 1009, areconstruction instruction portion 1010, a captured image thumbnail1011, an intended-for-imaging thumbnail 1012, a window level editingportion 1013, a window width editing portion 1014, an examinationsuspension instruction portion 1015, an image output instruction portion1016, an examination termination instruction portion 1017, an annotationdisplay instruction portion 1018, a clockwise instruction portion 1019,a counterclockwise instruction portion 1020, a horizontal inversioninstruction portion 1021, a vertical inversion instruction portion 1022,a white/black inversion instruction portion 1023, an L mark placementinstruction portion 1024, an R mark placement instruction portion 1025,a cropping setting instruction portion 1026, a mask processinginstruction portion 1027, a re-imaging button 1028, a reject button1029, an undo instruction portion 1030, and a reset instruction portion1031. The image display portion 1002 shows a preview of a captured imageobtained after still-image imaging or a tomosynthesis image subjected tothe reconstruction process. During moving-image imaging, captured imagesare displayed as previews in real time. If preview selection is switchedafter imaging, a captured image subjected to preview selection isdisplayed as a preview. In addition, patient information, examinationinformation, irradiation conditions, and so forth are displayed asannotations in accordance with the settings. No images are displayed inthe initial state immediately after the start of an examination. Thestatus display portion 1003 is an area in which the status notified bythe X-ray control unit 104 or the X-ray detector 106 is displayed usinga distinct color or text to allow the operator to distinguishablyidentify the status. Upon receipt of a notification of a status from theX-ray control unit 104 or the X-ray detector 106 via the communicationcircuit 112, the imaging control unit 405 notifies the examinationcontrol unit 406 of a change of the status. The examination control unit406 determines the displayed content in accordance with a combination ofstatuses of the X-ray control unit 104 or the X-ray detector 106, andtransmits a status display switching instruction to the display controlunit 4070. For example, if the X-ray control unit 104 is not capable ofX-ray irradiation or the X-ray detector 106 is not capable of X-raydetection, “Not Ready” is displayed on the sensor status. If the X-raycontrol unit 104 is capable of X-ray irradiation and the X-ray detector106 is capable of X-ray detection, “Ready” is displayed on the sensorstatus and the background color is changed to a color which is madeeasily distinguishable from that for the display of “Not Ready”. Thesingle-view instruction portion 1004 is a button for switching to asingle-view mode in which one frame of an image being selected as apreview is displayed in the image display portion 1002. In the case ofimages of a plurality of frames, it is also possible to display adifferent frame or reproduce a moving image during the display of apreview in accordance with a keyboard or mouse operation. The multi-viewinstruction portion 1005 is a button for switching to a multi-view modein which the image display portion 1002 is segmented into a plurality ofdisplay areas in a lattice pattern and images captured in theexamination being conducted are displayed in parallel. The button isdisabled and the multi-view mode is not available until two or moreimages are captured in the examination being conducted. The frame-viewinstruction portion 1006 is a button for switching to a frame-view modein which the image display portion 1002 is segmented into a plurality ofdisplay areas in a lattice pattern and frame images of a moving imagebeing selected as a preview are displayed in parallel. If the imagebeing selected as a preview is not a moving image, the button isdisabled and the frame-view mode is not available. The patientinformation display portion 1007 is an area in which patient informationsuch as the patient's name and a patient ID is displayed. Theexamination information display portion 1008 shows examinationinformation such as an examination ID or examination description.Further, imaging techniques selected in the examination are displayedside by side in the imaging technique display portion 1009. The imagingtechnique display portion 1009 includes the reconstruction instructionportion 1010, the captured image thumbnail 1011, and theintended-for-imaging thumbnail 1012. The imaging technique displayportion 1009 shows imaging technique information such as the name of animaging technique and all the captured image thumbnails 1011 that havebeen implemented. In the initial state immediately after the start of anexamination, no imaging has been performed and thus no captured imagethumbnails 1011 are displayed. The reconstruction instruction portion1010 is a button for providing an instruction to execute areconstruction process on a tomosynthesis imaging technique includingthe image currently being selected as a preview. The reconstructioninstruction portion 1010 is not displayed for imaging techniques otherthan tomosynthesis, and the display area is cut out. If a plurality oftomosynthesis imaging techniques are being displayed, all the buttonsother than a tomosynthesis imaging technique including the imagecurrently being selected as a preview are disabled. An instruction isgiven through the reconstruction instruction portion 1010, therebyenabling reconstruction to be re-performed on a tomosynthesis imagingtechnique which has been subjected to a reconstruction process once. Thecaptured image thumbnail 1011 has displayed thereon a thumbnail imagecorresponding to each captured image, an imaging type mark, a similaritymark 2301, and a reject mark 2701. The imaging type mark is a mark thatmakes the types of still-image imaging, fluoroscopic imaging, cineimaging, and tomosynthesis-image imaging distinguishable from oneanother. For example, cine imaging is represented by “C” andtomosynthesis-image imaging is represented by “T”. However, the marksare not limited thereto, and any sign capable of distinguishing imagingtypes from one another may be used. Selecting the captured imagethumbnail 1011 switches preview display. Further, the imaging techniquedisplay portion 1009 currently being selected as intended for the nextirradiation shows the intended-for-imaging thumbnail 1012, which isdisplayed as blank, at a location where an additional thumbnail is to beplaced when irradiation takes place next time. When the state of beingselected as intended for irradiation is released, theintended-for-imaging thumbnail 1012 is made invisible. The window levelediting portion 1013 and the window width editing portion 1014 areportions in which the window level and the window width of the imagecurrently being selected as a preview are edited. Changing the valuesdisplayed in the edit boxes or dragging the mouse on the image displayportion 1002 applies the editing to an image being displayed as apreview. The examination suspension instruction portion 1015 is a buttonfor providing an instruction to suspend the examination being conducted.The examination control unit 406 performs an examination suspensionprocess. The image output instruction portion 1016 is a button forproviding an instruction to output a captured image included in theexamination being conducted. A process flow when an image outputinstruction is given is similar to that for the image output process atthe end of the examination illustrated in FIG. 7. The examinationtermination instruction portion 1017 is a button for providing aninstruction to terminate the examination being conducted. Theexamination control unit 406 performs an examination terminationprocess. The annotation display instruction portion 1018 is a button forswitching the visibility of an annotation displayed in the image displayportion 1002. The clockwise instruction portion 1019 is a button forallowing a captured image being displayed as a preview to rotateclockwise. The counterclockwise instruction portion 1020 is a button forallowing a captured image being displayed as a preview to rotatecounterclockwise. The horizontal inversion instruction portion 1021 is abutton for horizontally inverting a captured image being displayed as apreview. The vertical inversion instruction portion 1022 is a button forvertically inverting a captured image being displayed as a preview. Thewhite/black inversion instruction portion 1023 is a button for invertingthe window value of a captured image being displayed as a preview. The Lmark placement instruction portion 1024 is a button for placing thelaterality marker “L” on a captured image being displayed as a preview.The button is on/off switchable, where “L” is placed when the button ison and “L” is removed when the button is off. The R mark placementinstruction portion 1025 is a button for placing the laterality marker“R” on a captured image being displayed as a preview. The button ison/off switchable, where “R” is placed when the button is on and “R” isremoved when the button is off. The cropping setting instruction portion1026 is a button for providing an instruction to set the croppingsettings for a region of interest in a captured image being displayed asa preview. The mask processing instruction portion 1027 is a button forproviding an instruction to perform mask processing on a captured imagebeing displayed as a preview. The re-imaging button 1029 is a button forproviding an instruction to perform re-imaging on an imaging techniqueincluding an image currently being selected as a preview. The termre-imaging, as used herein, refers to a process for executing a rejectprocess on an image specified in a re-imaging instruction and newlyadding the same imaging technique. The reject button 1029 is a buttonfor providing a reject instruction for an image currently being selectedas a preview. When a reject process is executed, a reject settingincluded in the image information is switched to ON. The undoinstruction portion 1030 is a button for providing an instruction toperform undo processing to return a history of processes on an imagecurrently being selected as a preview to a new order. The resetinstruction portion 1031 is a button for providing an instruction toperform a reset process for discarding all the processes for an imagecurrently being selected as a preview and returning the state to a stateobtained immediately after imaging. The imaging screen 1001 having theconfiguration described above is displayed.

The display control unit 4070 causes an imaging technique for capturinga projected image group to be displayed in the imaging technique displayportion 1009 (first display area) on the foregoing imaging screen 1001.In response to the capture of a projected image group corresponding tothe imaging technique, a captured image thumbnail 1011 representing theprojected image group is displayed in the imaging technique displayportion 1009. Further, in response to the generation of a tomosynthesisimage based on the projected image group, the display control unit 4070causes a captured image thumbnail 1011 of the tomosynthesis image to bedisplayed in the imaging technique display portion 1009 (first displayarea). Doing so provides an intelligible display of imaging informationand its corresponding projected image group and tomosynthesis image.

Next, an example of the reconstruction screen 1101 displayed in stepS609 in FIG. 6 is illustrated using FIG. 11. The reconstruction screen1101 is constituted by an image display portion 1102, a frame specifyingslider 1103, an image operation toolbar 1104, a coronal cross sectiondisplay instruction portion 1105, an oblique cross section displayinstruction portion 1106, a frame-view instruction portion 1107, areconstruction method selection portion 1108, a reconstruction filtertype selection portion 1109, a reconstruction filter DC editing portion1110, a cutoff frequency editing portion 1111, a tomographic pitchediting portion 1112, a number-of-slice editing portion 1113, a noisereduction process editing portion 1114, a reconstruction processinstruction portion 1115, a default settings instruction portion 1116, aframe reproduction range setting portion 1117, a window adjustmentdisplay instruction portion 1118, a reproduction process displayinstruction portion 1119, a reconstruction cancellation instructionportion 1120, a reconstruction confirmation instruction portion 1121,and a 3D slider 1122. The image display portion 1102 shows a preview ofa tomosynthesis image subjected to the reconstruction process. Duringthe ongoing reconstruction process, a progress bar notifying the userthat the reconstruction process is in progress is displayed, and atomosynthesis image is displayed at the same time as the completion ofthe reconstruction process. The frame specifying slider 1103 is used tocheck a frame image being displayed in a tomosynthesis image beingdisplayed as a preview and to switch between frame images. At the sametime as the display of a preview of the tomosynthesis image, memoriesfor all the valid frames of the tomosynthesis image being displayed as apreview are equally displayed from the upper end to the lower end alongthe slider. Control is performed so that only valid frames can bespecified, thereby reducing the risk of erroneous display of invalidframes. A frame having a number corresponding to a memory selected byselection or dragging across the frame specifying slider 1103 isdisplayed in the image display portion 1102. The image operation toolbar1104 has arranged thereon controls for providing instructions to performprocesses on the tomosynthesis image being displayed as a preview. Thearranged controls are similar to 918 to 931 on the imaging screen 1001.

The coronal cross section display instruction portion 1105 is a buttonfor providing an instruction that the tomosynthesis image displayed inthe image display portion 1102 be displayed on a coronal cross section,and corresponds to a button for providing an instruction to display afirst two-dimensional tomographic image. This button is made selectablein the initial state where the reconstruction screen 1101 in FIG. 11 isdisplayed, and is also in an on state (selected state). The obliquecross section display instruction portion 1106 is a button for providingan instruction that the tomosynthesis image displayed in the imagedisplay portion 1102 be displayed on an oblique cross section, andcorresponds to a button for providing an instruction to display a secondtwo-dimensional tomographic image.

The frame-view instruction portion 1107 is a button for switching to aframe-view mode in which the image display portion 1102 is segmentedinto a plurality of display areas in a lattice pattern and frame imagesof a tomosynthesis image being displayed as a preview are displayed inparallel. The button is disabled and frame-view display is not availableduring oblique cross section display. The reconstruction methodselection portion 1108 is a control for selecting a reconstructionmethod such as the FBP (Filtered Back Projection) method, theshift-and-add method, or the iterative reconstruction method. Thereconstruction filter type selection portion 1109 is a control forselecting the type of a filter to be used for the reconstructionprocess. The reconstruction filter DC editing portion 1110 is a controlfor editing the DC parameter for the filter to be used for thereconstruction process. The cutoff frequency editing portion 1111 is acontrol for editing the cutoff frequency of the filter to be used forthe reconstruction process. The tomographic pitch editing portion 1112is a control for editing the thickness between frames during thereconstruction process. The number-of-slice editing portion 1113 is acontrol for editing the total number of frames during the reconstructionprocess. The noise reduction process editing portion 1114 is a controlfor switching whether or not to apply a noise reduction process duringthe reconstruction process and for editing the degree of severity of theapplication of the noise reduction process. The reconstruction processinstruction portion 1115 is a button for providing an instruction toexecute a reconstruction process. Reconstruction is executed again byusing a reconstruction parameter that has been input at the time whenthe button is pressed. In this case, the same projected images as thosefor the tomosynthesis image being displayed as a preview are used. Thedefault settings instruction portion 1116 is a button for providing aninstruction to change the default reconstruction parameters of thetomosynthesis imaging technique being displayed as a preview. When thebutton is pressed, a reconstruction parameter change notificationtogether with the currently displayed reconstruction parameters istransmitted from the imaging control unit 405 to the examination controlunit 406. The examination control unit 406 updates the reconstructionparameters of the tomosynthesis imaging technique which is the target ofthe reconstruction parameters, and transmits a “registration/update”process request to the imaging technique information storage unit 402.The frame reproduction range setting portion 1117 is a control forspecifying a reproduction range during range-specified reciprocalreproduction. The frame reproduction range setting portion 1117 isconstituted by knobs for specifying a minimum frame number, a centerframe number, and a maximum frame number. Moving the respective knobsallows a range from the specified minimum frame number to the specifiedmaximum frame number to be set as a reproduction range. The windowadjustment display instruction portion 1118 is a button for switchingthe visibility of a window adjustment control. When the windowadjustment display instruction portion 1118 is switched to ON, a windowadjustment portion 1601 is displayed in the 3D slider 1122 display area.

The image processing unit 110 according to the embodiment performs ananalysis process of a tomosynthesis image, and subjects a slice imagegenerated from the tomosynthesis image, such as a coronal image or anoblique image, to tone conversion processing such as window processing.The display control unit 4070 causes the slice image subjected to thewindow processing to be displayed in the image display portion 1102 onthe reconstruction screen 1101.

When the window adjustment display instruction portion 1118 is switchedto OFF, the window adjustment portion 1601 is made invisible and the 3Dslider 1122 is displayed. The reproduction process display instructionportion 1119 is a button for switching the visibility of a reproductionprocess control. When the reproduction process display instructionportion 1119 is switched to ON, a reproduction processing portion 2001is displayed in the 3D slider 1122 display area. When the reproductionprocess display instruction portion 1119 is switched to OFF, thereproduction processing portion 1601 is made invisible and the 3D slider1122 is displayed. The reconstruction cancellation instruction portion1120 is a button for providing an instruction to discard thetomosynthesis image being previewed. When an instruction for cancelingreconstruction is given, step S609 is completed without the storage ofthe tomosynthesis image and the image information, and a transition tothe imaging screen 1001 occurs. On the imaging screen 1001, an imagewhich has been previewed before the reconstruction screen is displayedis continuously selected as a preview. The reconstruction confirmationinstruction portion 1121 is a button for providing an instruction toconfirm the storage of the tomosynthesis image being previewed. When aninstruction for confirming the storage is given, the tomosynthesis imagebeing previewed is saved in the HDD 504. Thereafter, step S608 iscompleted, and a transition to the imaging screen 1001 occurs.

The 3D slider 1122 is a control for providing a pseudo-3D display of aframe of the generated tomosynthesis image and specifying a displayframe. The 3D slider 1122 has displayed thereon ruled lines depicting arelative positional relationship between frames of each tomosynthesisimage, and a small image is displayed at the position of the same framenumber as a display frame image. Selecting a ruled line on the 3D slider1122 or dragging the mouse can facilitate switching between displayframes. As the ruled lines displayed on the 3D slider 1122, those foronly valid frames of a tomosynthesis image are displayed. In addition,in association with the editing of the tomographic pitch or the numberof slices, the positional relationship between frames of eachtomosynthesis image subjected to the reconstruction process is displayedas a preview so as to be superimposed on the current state. This enablesthe operator to easily understand a change in thickness when changingthe tomographic pitch or the number of slices. The reconstruction screen1101 having the configuration described above is displayed.

Next, the reconstruction screen 1101 displayed in step S609 in FIG. 6for the display of an oblique cross section is illustrated using FIG.12. When the oblique cross section display instruction portion 1106 ispressed, the cross section of the tomosynthesis image displayed in theimage display portion 1102 is switched from a coronal cross-sectionalimage to an oblique cross-sectional image. When the coronal crosssection display instruction portion 1105 is pressed, the cross sectionof the tomosynthesis image displayed in the image display portion 1102is switched from a coronal cross section to an oblique cross section.During the display of an oblique cross section, the specification of aframe by using the frame specifying slider 1103 or any reproductioninstruction from the reproduction processing portion 1901 is ignored. Inaddition, the frame-view instruction portion 1107 is disabled, and theframe-view mode is not available. During the display of an oblique crosssection, an oblique-angle editing 3D slider 1201 is displayed in placeof the typical 3D slider 1122. The oblique-angle editing 3D slider 1201is a display area in which posture information of an obliquecross-sectional image displayed in the image display portion 1102appears. In the oblique-angle editing 3D slider 1201, a direction alongan upper surface and a lower surface of an illustrated rectangularparallelepiped corresponds to the direction of a coronal cross-sectionalimage, and a presentation of posture information of an obliquecross-sectional image crossing the coronal cross-sectional image isprovided.

Further, the oblique cross-sectional image illustrated in FIG. 12 is animage of a cross section that always extends through the isocenter. Theisocenter is represented as a cross mark on a side surface of theillustrated rectangular parallelepiped. In another embodiment, the imageprocessing unit 110 generates an oblique cross-sectional image at aposition that does not pass through the isocenter, and the displaycontrol unit 4070 can cause the oblique cross-sectional image to bedisplayed in accordance with the operation input from the operation unit108.

The editing of the display angle of a frame image displayed on theoblique-angle editing 3D slider 1201 results in the oblique angle beingchanged accordingly. In association with the oblique angle edited in theoblique-angle editing 3D slider 1201, the oblique angle of thetomosynthesis image displayed as a preview in the image display portion1102 is also changed. The reconstruction screen 1101 having theconfiguration described above for the display of an oblique crosssection is displayed.

<Oblique Display Limitation Process>

Here, an example of a process related to the display of a reconstructionscreen from the start of irradiation for projected images, which isexecuted in step S608 and step S609 in FIG. 6, is illustrated using FIG.13. The process illustrated in FIG. 13 is performed by, for example, theimaging control device 107 illustrated in FIG. 1. First, in step S1301,the irradiation switch 103 is pressed to start irradiation, andprojected images are sequentially captured.

In S1302, the pressing of the irradiation switch 103 is released toterminate irradiation, and the capture of projected images is completed.Upon receipt of a projected image irradiation end notification, theimaging control unit 405 transmits an imaging interruption determinationrequest notification to the imaging interruption determination unit 401.The imaging interruption determination request notification includesimage information on the projected images, and position information.

Here, the imaging interruption determination unit 401 determines thesituation in which interruption of imaging is occurring by using theimage information on the projected images and the position information,and notifies the imaging control unit 405 of an imaging interruptiondetermination result. The imaging interruption determination resultincludes a determination status, the determination status including “noposition information”, “interrupted in initial stage”, “interrupted inlater stage”, and “completed”.

In step S1303, upon receipt of the imaging interruption determinationrequest notification, the imaging interruption determination unit 401checks the position information. If no position information is included,the imaging interruption determination unit 401 sets the determinationstatus to “no position information”, and transmits the imaginginterruption determination result to the imaging control unit 405.

If position information is included, in step S1304, the progress levelmeasuring unit 4011 checks the imaging state. The progress levelmeasuring unit 4011 refers to either the imaging angle included in theposition information or the X-ray detector moving distance, anddetermines a maximum value (FIG. 3). If the maximum value is a negativevalue, the imaging interruption determination unit 401 determinesinterruption of the imaging at less than 0°, and sets the determinationstatus to “interrupted in initial stage”. If the initial position at thestart of imaging begins with a positive value, the imaging interruptiondetermination unit 401 refers to either the imaging angle included inthe position information or the X-ray detector moving distance, anddetermines a minimum value. If the minimum value is a positive value,the imaging interruption determination unit 401 determines that theimaging has been interrupted at less than 0°, and sets the determinationstatus to “interrupted in initial stage”. Subsequently, the progresslevel measuring unit 4011 compares the maximum value of the imagingangle or X-ray detector moving distance with the maximum imaging angleincluded in the default imaging conditions or the maximum X-ray detectormoving distance. If the maximum value of the position information isless than the maximum imaging angle or the maximum X-ray detector movingdistance by a certain threshold value, the imaging interruptiondetermination unit 401 determines interruption of the imaging at 0° orgreater, and sets the determination status to “interrupted in laterstage”. If the minimum value of the imaging angle or X-ray detectormoving distance is used, the minimum value is compared with the minimumimaging angle included in the default imaging conditions or the minimumX-ray detector moving distance. Thereafter, the imaging interruptiondetermination unit 401 transmits the imaging interruption determinationresult to the imaging control unit 405.

Upon receipt of the imaging interruption determination result, theimaging control unit 405 checks the determination status. If thedetermination status indicates “no position information”, “interruptedin initial stage”, or “interrupted in later stage”, the imaging controlunit 405 transmits an imaging interruption notification to theexamination control unit 406. Upon receipt of the imaging interruptionnotification, the examination control unit 406 updates the status of thetarget imaging technique information.

Then, in step S1305, the examination control unit 406 checks the statusof the imaging technique information.

If the status indicates “no position information” in step S1305, then instep S1312, the examination control unit 406 displays a pop-up screen1401 on the imaging screen 1001. When the pop-up screen 1401 is closed,the examination control unit 406 ends the process without a transitionto a reconstruction screen.

If the status indicates “initial stage” in step S1305, then in stepS1313, the examination control unit 406 displays a pop-up screen 1601 onthe imaging screen 1001. When the pop-up screen 1601 is closed, theexamination control unit 406 transmits a reconstruction prohibitionnotification to the display control unit 4070 without a transition to areconstruction screen. The reconstruction transmission notificationincludes imaging technique information.

Then, in step S1316, upon receipt of the reconstruction prohibitionnotification, the display control unit 4070 transmits the reconstructionprohibition notification to the display unit 109. Upon receipt of thereconstruction prohibition notification, the display unit 109 disablesthe display of the reconstruction instruction portion 1010 in theimaging screen 1001, and then the process ends.

If the to-be-implemented determination status indicates “completed” instep S1305, then in step S1306, the imaging control unit 405 comparesthe number of acquired frames of projected images with the number ofelements of position information.

If the number of acquired frames of projected images is different fromthe number of elements of position information in step S1306, then instep S1307, the imaging control unit 405 carries out a correctionprocess to make the number of acquired frames of projected images andthe number of elements of position information identical. At the sametime, the imaging control unit 405 transmits a correction processaccomplishment notification to the examination control unit 406. Uponreceipt of the correction process accomplishment notification, theexamination control unit 406 updates information on the presence orabsence of a correction process for the target imaging techniqueinformation.

If the number of acquired frames of projected images and the number ofelements of position information are identical in step S1306, nocorrection process is carried out.

In step S1308, the imaging control unit 405 carries out a reconstructionprocess. The process flow of steps S1308 to S1309 is similar to theprocess flow of S608 to S609 in FIG. 6. After a tomosynthesis image hasbeen displayed on the reconstruction screen 1101, in step S1310, theexamination control unit 406 checks the status of imaging techniqueinformation including the displayed tomosynthesis image.

In the way described above, even if the imaging ends in step S1302 dueto the interruption of the imaging, in the situation where the imagingproceeds at 0° or greater (half or more finished), in S1308, the imageprocessing unit 110 is caused to execute a reconstruction process on thebasis of projected images obtained through the interrupted imaging.Then, a coronal image (first two-dimensional tomographic image) isdisplayed. In contrast, the display of an oblique image (secondtwo-dimensional tomographic image) is prohibited, leading to lesslikelihood of false diagnosis.

In addition, in the way described above, even if the imaging ends instep S1302 due to the interruption of the imaging, the processes fromstep S1303 to step S1308 are sequentially executed, thereby enabling areconstruction process to be started based on projected images obtainedin accordance with the interrupted imaging. This enables a diagnosticimage to be efficiently obtained while saving the time and labor of theoperator.

Here, in another embodiment, only when the imaging ends due to theinterruption of the imaging, the display control unit 4070 causes thedisplay unit 109 to display a GUI for accepting an operation inputindicating whether or not to start a reconstruction process before theimage processing unit 110 executes the reconstruction process in stepS1308. The GUI includes, for example, a message indicating “The imaginghas been interrupted but you can perform a reconstruction process on acoronal image. Do you wish to start a reconstruction process?”, and apop-up window having an OK button and a Cancel button which can bepressed in accordance with an operation of the operation unit 108. Thispop-up window is displayed superimposed on, for example, the examinationscreen illustrated in FIG. 10. When the input detection unit 4071detects the pressing of the OK button in accordance with the operationinput from the operation unit 108, the imaging control unit 405 causesthe image processing unit 110 to start a reconstruction process inaccordance with the detection. Doing so can reduce the execution of areconstruction process unnecessary for the user, and achieve efficientexecution of tomosynthesis imaging.

In step S1310, the display control unit 4070 limits the display of atwo-dimensional tomographic image intersecting the detection surface ofthe X-ray detection unit in accordance with the degree of progress ofimaging of projected images. If the status indicates “interrupted inlater stage”, in step S1314, the examination control unit 406 displays apop-up screen 1601 on the reconstruction screen 1101. When the pop-upscreen 1601 is closed, the examination control unit 406 transmits anoblique display prohibition notification to the display control unit4070.

Then, in step S1317, upon receipt of the oblique display prohibitionnotification, the display control unit 4070 transmits the obliquedisplay prohibition notification to the display unit 109. Upon receiptof the oblique display prohibition notification, the display unit 109disables the display of the oblique display instruction portion 1106 onthe reconstruction screen 1101, and limits the display of atwo-dimensional tomographic image (second two-dimensional tomographicimage, oblique image) intersecting the detection surface of the X-raydetector 106.

In the manner described above, if it is determined that the imaging hasbeen interrupted by using the position information from the X-raycontrol unit 104, the display control unit 4070 performs control so thatthe oblique display instruction portion 1106 for providing aninstruction to display an oblique image (second two-dimensionaltomographic image) is not selectable. Accordingly, the display of anoblique image is prohibited. Doing so can reduce the probability that animage which is diagnostically inappropriate for the user will bedisplayed.

If the status does not indicate “interrupted in later stage” in stepS1310, then in step S1311, the examination control unit 406 checksinformation on the presence or absence of a correction process for theimaging technique information.

If a correction process is present in step S1311, then in step S1315,the examination control unit 406 displays a pop-up screen 1701 on thereconstruction screen 1101. When the pop-up screen 1701 is closed, theexamination control unit 406 transmits an oblique display permissionnotification to the display control unit 4070.

In step S1318, upon receipt of the oblique display permissionnotification, the display control unit 4070 transmits the obliquedisplay permission notification to the display unit 109. Upon receipt ofthe oblique display permission notification, the display unit 109enables the display of the oblique display instruction portion 1106 onthe reconstruction screen 1101, and then the process ends.

In the example described above, after the image processing unit 110 hascarried out a reconstruction process of three-dimensional volume data inS1308, the display control unit 4070 limits display in S1317 or thelike. However, the embodiment is not limited thereto. In anotherexemplary embodiment, prior to the process of step S1318, the imageprocessing unit 110 directly reconstructs a plurality of oblique images(second two-dimensional tomographic images) from projected images. Thisallows oblique images to be directly reconstructed from projectedimages, and can improve image quality. On the other hand, if the processproceeds to step S1314, the oblique image generation process is notperformed by the control of the imaging control unit 405. By doing so,no generation process is performed for unnecessary oblique images,leading to efficient processing.

An example of the pop-up screen 1401 displayed on the reconstructionscreen 1101 when it is judged in step S1312 in FIG. 13 that there is nonotification of position information is illustrated using FIG. 14(a).The pop-up screen 1401 is displayed on the imaging screen 1001. Thepop-up screen 1401 shows a message indicating that reconstruction is notavailable since there is no notification of position information, and anOK button 1402. When the OK button 1402 is pressed, the pop-up screen1401 is closed, making an operation available on the imaging screen1001. The pop-up screen 1401 having the configuration described above isdisplayed. Note that position information may possibly be transmittedlater with a delay. Accordingly, the display of the reconstructionprocess instruction portion 1010 is enabled, and, if a notification ofposition information has been received at the time of pressing,reconstruction is carried out. If no notification of positioninformation has been received at the time of pressing, the pop-up screen1401 is displayed again.

An example of a pop-up screen 1403 displayed on the reconstructionscreen 1101 when it is judged in step S1313 in FIG. 13 that the captureof projected images has been interrupted at less than 0° is illustratedusing FIG. 14(b). The pop-up screen 1403 is displayed on the imagingscreen 1001. The pop-up screen 1403 shows a message indicating thatreconstruction is not available since the imaging has been interrupted,and an OK button 1404. When the OK button 1404 is pressed, the pop-upscreen 1401 is closed, making an operation available on the imagingscreen 1001. In addition, for an imaging technique for which the captureof projected images has been interrupted at less than 0°, thereconstruction process instruction portion 1010 is disabled, and it isnot possible to execute reconstruction. For example, displaying a crossmark 1405 over the reconstruction process instruction portion 1010enables the disablement of the reconstruction process instructionportion 1010 to be more clearly presented.

Here, an example of a pop-up screen 1501 displayed on the reconstructionscreen 1101 when the capture of projected images has been interrupted at0° or greater in step S1314 in FIG. 13 is illustrated using FIG. 15. Thepop-up screen 1501 is displayed on the reconstruction screen 1101. Thepop-up screen 1501 shows a message indicating that reconstruction mightnot have been correctly performed since the imaging has been interruptedand that the display of oblique cross sections now becomes unavailable,and an OK button 1502. When the OK button 1502 is pressed, the pop-upscreen 1501 is closed. In addition, if the capture of projected imageshas been interrupted at 0° or greater, the oblique cross section displayinstruction portion 1106 is disabled, making the display of an obliquecross section unavailable. For example, displaying a cross mark 1503over the oblique cross section display instruction portion 1106 enablesthe disablement of the oblique cross section display instruction portion1106 to be more clearly identified.

As in FIG. 14(b) and FIG. 15 described above, the display control unit4070 causes a warning to be displayed at the time of the interruption ofimaging, allowing it to be clarified that the imaging has beeninterrupted before the imaging of a predetermined range has beencompleted. In addition, as in FIG. 15, the display control unit 4070causes a different warning to be displayed in accordance with the levelof progress of imaging or the degree of advancement, allowing the userto readily recognize that a different process has been performed inaccordance with the degree of advancement.

In another embodiment, even if it is determined in step S1310 that aninterruption has occurred in the situation of imaging at 0° or greater,the oblique cross section display button is not disabled. This impliesthat whether an image can be used for diagnosis or not is deferred tothe judgment of a person who is responsible for diagnosis, and thedisplay control unit 4070 causes the display unit 109 to display anoblique image based on an X-ray projected image obtained by exposing theperson being examined to X-rays. In this case, the display control unit4070 performs display control to, when displaying an oblique image, alsodisplay an indication of a diagnostically unsuitable image. For example,the indication of a diagnostically unsuitable image is, for example, amessage indicating “The quality of reconstructed images might beaffected as a result of the interruption of the desired imagingoperation”, and, in addition, the display control unit 4070 causes anoblique image to be displayed. Alternatively, in a case where an obliqueimage of a certain posture is output to outside as a DICOM image, theimage processing unit 110 embeds the text message described above intothe image as image data. This can lead to less likelihood of falsediagnosis because such an image may be misinterpreted as an imagecaptured through a correct procedure.

In another embodiment, for example, the following situation isconsidered. Settings are made such that projected images obtained atirradiation positions from −30° to +30° are captured. It is assumedthat, because of the interruption of imaging, only projected images from−30° to +10° have been successfully obtained. In this case, it isconsidered that quality equal to or more than that for reconstructedimages based on projected images obtained at irradiation positions fromat least −10° to +10° is assured. In addition, in a case where projectedimages are obtained by imaging over a range of ±30°, it is assumed thatthe intersection angle of an oblique image can be varied up to ±30°. Ina case where projected images are obtained by imaging over a range of±10°, it is assumed that the intersection angle of an oblique image canbe varied up to ±10°. In this case, the display control unit 4070performs control so that an oblique image based on projected imagesobtained through the interrupted imaging described above has anintersection angle which is variable over a range of ±10°.

Accordingly, in the manner described above, if imaging is interruptedmidway under a first imaging condition, this situation is handledsimilarly to that for a second imaging condition which at least providesequal or higher image quality based on projected images obtained beforeinterruption and based on position information. Specifically, thedisplay control unit 4070 causes the display of oblique images over arange similar to that when imaging is performed under the second imagingcondition.

By doing so, even if imaging is interrupted, obtained X-ray projectedimages can be effectively utilized as long as image quality is assured.

In the embodiment described above, the communication circuit 112 of theimaging control device 107 transmits driving conditions and alsotransmits irradiation conditions for the X-ray generation unit 102.However, the embodiment is not limited thereto. For example, irradiationconditions for the X-ray generation unit may be directly input throughan operation unit (not illustrated) of the X-ray control unit 10, andthe communication circuit 112 may receive the input irradiationconditions serving as setting conditions and irradiation conditionsserving as execution information used for the actual imaging.

Examples of the reconstruction algorithm for the image processing unit110 may also include the iterative reconstruction method in addition tothe FBP method (Filtered Back Projection) and the shift-and-add method.

While the emission of pulsed X-rays has been described in the embodimentdescribed above, this is not to be taken in a limiting sense.Alternatively, X-rays may be continuously emitted, and the X-raydetector may detect the X-rays to obtain projected images. In this case,the positions of the X-ray generation unit 102 and the X-ray detector106 differ between at the start of X-ray irradiation and at the end ofX-ray irradiation in terms of units of projected images. In this case,it may be sufficient to perform a reconstruction process by using apositional relationship obtained at a certain timing from the start ofX-ray irradiation to the end of X-ray irradiation as geometricinformation for which the projected images have been captured.

In the embodiment described above, the imaging control device 107illustrated in FIG. 4 or FIG. 16 is configured to execute the obliquedisplay control illustrated in S1317 and S1318 in FIG. 13, thecorrection process and a notification thereof illustrated in S1307 andS1315, the valid frame determination illustrated in FIG. 19, theprocesses illustrated in FIG. 21, FIG. 23, and FIG. 25, and so forth.However, the embodiment is not limited thereto. For example, an imageprocessing device or an image management device, such as the PACS 115 orthe viewer 116 illustrated in FIG. 1, may be configured to execute theprocesses according to the embodiment described above. The processes areexecuted by the imaging control device, enabling the X-ray imagingsystem 101 to make detailed studies and providing efficient imaging.Accordingly, repetitions of imaging can be reduced and efficient X-rayimaging can be achieved.

An imaging control device 107 according to a different embodiment of thepresent invention will be described with reference to FIG. 16. Theelements assigned numerals similar to the numerals illustrated in FIG. 4have configurations and functions similar to those in FIG. 16 unlessotherwise stated. The imaging control device 107 according to thisembodiment further includes a correspondence correction unit 1601, acondition comparison unit 1602, a valid frame determination unit 1604,and a tone conversion processing execution determination unit 1608.Additionally, the image processing unit 110 includes a reconstructionprocessing unit 1611, a tone conversion parameter acquisition unit 1612,and a tone conversion processing unit 1613. The image processing unit110 and the communication circuit 112 are incorporated in the controlunit 111. For example, the image processing unit 110 is implemented bythe CPU 501 illustrated in FIG. 5. Note that, for example, in the imageprocessing unit 110, only the reconstruction processing unit 1611 may beimplemented by a circuit separate from the control unit 111, forexample, by a dedicated GPU. Further, the communication circuit 112 isnot designed to be connected to the control unit 111, and is a circuitblock formed integrally with the control unit 111.

The reconstruction processing unit 1611 of the image processing unit 110reconstructs a tomosynthesis image on the basis of a plurality ofprojected images and position information such as an irradiationdirection. For reconstruction, various reconstruction conditions,including reconstruction methods such as the FBP and the iterativereconstruction method, filter types such as the Lamp filter, the Shepp &Logan filter, and the Chesler filter, filter settings such as a filterDC and a cutoff frequency, tomographic settings such as a tomographicpitch, the number of tomograms, and a reconstruction range, and aparameter for a noise reduction process, are set. A reconstructionprocess is performed based on these setting parameters.

The tone conversion parameter acquisition unit 1612 acquires parametersor tone conversion conditions for performing tone conversion processingof a tomosynthesis image. The tone conversion conditions include, forexample, a window level and a window width for determining a tone. Forexample, the tone conversion parameter acquisition unit 1612 analyzes ahistogram of tomographic images at the isocenter position of thetomosynthesis image to acquire the parameters of the window level andthe window width. In another case, the condition setting unit 4051generates setting information in accordance with the operation inputfrom the operation unit 108, and the tone conversion conditions areinput to the image processing unit 110 through the imaging control unit405. In this case, the tone conversion parameter acquisition unit 1612acquires the input tone conversion conditions. The tone conversionparameter acquisition unit 1612 inputs the acquired tone conversionconditions to the tone conversion processing unit 1613.

The tone conversion processing unit 1613 performs tone conversionprocessing on the tomosynthesis image by using the obtained toneconversion conditions. For example, the tone conversion processing unit1613 performs tone conversion processing on a two-dimensionaltomographic image obtained based on the tomosynthesis image.

As described above, the image processing unit 110 generates atomosynthesis image in accordance with a plurality of projected imagesand set process conditions such as reconstruction conditions and toneconversion conditions.

The correspondence correction unit 1601 corrects a correspondencerelationship between a set of pieces of position information on theX-ray detector 106 and the X-ray generation unit 102, which is obtainedfrom the X-ray control unit 104 via the communication circuit 112, and aset of projected images obtained from the X-ray detector 106 via thecommunication circuit. If the projected images and the pieces ofposition information are not in one-to-one correspondence for thereasons such as a mismatch between the number of projected images andthe number of pieces of position information and missed timing due to adevice error or depending on the specifications, the correspondencecorrection unit 1601 performs a process of performing correction byfinding an appropriate pair. This allows the generation of areconstructed image without wasting projected images, and contributes toa reduction in the radiation exposure of the object. The processingresult of the correspondence correction unit 1601 is output to theimaging control unit 405, and the display control unit 4070 causes amessage corresponding to the processing result to be displayed. Thedetails of the correspondence correction process will be described belowwith reference to FIG. 17 and FIG. 18.

The valid frame determination unit 1604 determines an invalid image areain accordance with the position information on the X-ray generation unit102 and the X-ray detector 106 obtained from the X-ray generationapparatus through the communication circuit 112. The invalid image areacorresponds to, for example, an area outside the object or an area awayfrom the X-ray generation unit 102 more than from the detection surfaceof the X-ray detector 106, which is computationally obtained. Thedisplay control unit 4070 causes the display unit 109 to display thetomosynthesis image obtained in accordance with the determinationresult. This enables a tomosynthesis image to be displayed while takinginto account an invalid image area. The details of the display processthat takes into account an invalid image area will be described belowusing FIG. 19 and FIG. 20.

The tone conversion processing execution determination unit 1608determines whether or not to execute tone conversion processing of thetomosynthesis image, in accordance with the settings of thereconstruction conditions or process conditions. In this case, if thecondition setting unit 4051 sets reconstruction conditions and toneconversion conditions, the tone conversion processing executiondetermination unit 1608 compares the conditions before and after thechange, and determines whether or not a setting has been made to changethe conditions. If a change has been made, the imaging control unit 405controls whether or not to use the tone conversion conditions after thechange for tone conversion processing on a tomosynthesis imagereconstructed under the reconstruction conditions after the change.Here, if the reconstruction method has been changed, the tone conversionprocessing conditions after the change are not used. The tone conversionparameter acquisition unit 1612 analyzes a tomosynthesis imagereconstructed using the reconstruction method after the change andacquires tone conversion conditions, and the tone conversion processingunit 1613 performs tone conversion processing.

Accordingly, appropriate image processing in accordance with a change inconditions can be executed. The details of the control as to whether toexecute tone conversion processing will be described below withreference to FIG. 21 and FIG. 22.

The condition comparison unit 1602 compares a variety of processconditions set by the condition setting unit 4051, and outputs thecomparison result to the imaging control unit 405. The imaging controlunit 405 controls the processes performed by the display control unit4070 and the image processing unit 110 in accordance with the processingresult of the condition comparison unit 1602.

The condition comparison unit 1602 contributes to additional displaycontrol of a captured image thumbnail 1011 that is an icon indicating atomosynthesis image displayed on the imaging screen 1001 illustrated inFIG. 10 or the like. The condition comparison unit 1602 compares theprocess conditions set by the condition setting unit 4051 with theprocess conditions for the tomosynthesis image already generated by theimage processing unit 110. The display control unit 4070 controlswhether or not to display a new icon corresponding to the set processconditions, in accordance with the comparison result. This canfacilitate comparison of a plurality of tomosynthesis images whilesuppressing an unnecessary increase in icons. The details of theadditional display control of an icon will be described below withreference to FIG. 23 and FIG. 24.

The data described above includes data of a projected image groupconstituted by a plurality of projected images or data of atomosynthesis image obtained on the basis of the projected image group.The condition setting unit 4051 sets at least one of the data of thetomosynthesis image or the data of the projected image group as areject. The reject setting functions as the setting of outputconditions. The image output control unit 409 limits the transmission ofthe data set as a reject to the external device. In response to thesetting of the data of the projected image group as a reject, thecondition setting unit 4051 sets, as a reject, data of a tomosynthesisimage generated based on the projected image group. Accordingly, if itis determined that the projected image group is not appropriate for theuser as a diagnostic target, data of a tomosynthesis image obtainedbased on the inappropriate projected image group is also set as areject, which can reduce the probability of inappropriate data beingoutput to outside. The details of the reject process will be describedbelow using FIGS. 25 to 28.

Any one or any combination of the correspondence correction processdescribed above, the display process taking into account an invalidimage area, the control as to whether to execute tone conversionprocessing, the additional display control of an icon, and the rejectprocess may be configured to be executable. These processes may also beindependently executed without being combined with the oblique displaylimitation process illustrated in the example described above.

The advantages of the processes according to the foregoing embodimentwill be described. Tomosynthesis imaging which enables reconstruction ofan arbitrary tomographic image requires involves a plurality of framesto be captured from the object in a single session for capturingprojected images. Thus, several seconds are required as an imagingperiod of time from the start to the end of imaging. This may causeirradiation to be interrupted without the completion of the desiredimaging due to a motion of the object or an operational error. In thiscase, even if reconstruction is successful, a tomosynthesis image willprobably not be generated with the desired accuracy. The same applies tothe display of an oblique cross section. In interrupted imaging,complete prohibition of reconstruction may cause waste of even imageswhich can be used for reconstruction, leading to increased radiationexposure of the object. In contrast, if a tomosynthesis image isdisplayed in a normal way through the reconstruction from projectedimages obtained in the interrupted imaging, it will be difficult torecognize that the tomosynthesis image may have been generated withaccuracy different from that for the desired image.

The embodiment described above enables a reconstruction process to beperformed as much as possible by effectively using captured images inaccordance with the situation even if the imaging has been interrupted.In addition, an available process is distinguishably controlled inaccordance with the situation in which interruption of imaging isoccurring, leading to less likelihood of false diagnosis by an operator.It is also possible to judge the availability of reconstruction and theavailability of the display of an oblique cross section in accordancewith the situation in which interruption of imaging is occurring,preventing an increase in the radiation exposure of the object withoutreadily wasting captured images. In addition, an operator is notified ofthe content of control based on the situation in which interruption ofimaging is occurring, so that the operator can recognize the differencebetween the interruption and the completion of imaging, leading to lesslikelihood of false diagnosis.

The imaging control unit 405 of the imaging control device 107 havingthe configuration illustrated in FIG. 16 performs the process of stepS609 in FIG. 6 described above, so that the imaging control unit 405determines, as valid frames, only a region including the object within atomosynthesis image frame group by using the reconstruction parametersand the position information (FIG. 19). Accordingly, invalid frames arecontrolled so as not to be stored, preventing an unnecessary frame imagefrom being displayed as a preview and making it possible to save thestorage capacity for the storage of images. Upon receipt of thereconstruction completion notification, the examination control unit 406generates new tomosynthesis image information, and receives the input ofthe tomosynthesis image, the reconstruction parameters, and the imageprocessing parameters, which are included in the reconstructioncompletion notification. Thereafter, the examination control unit 406adds the newly generated tomosynthesis image information to an imagingtechnique for which reconstruction has been completed within the imagingtechnique information included in theexamination-scheduled-to-be-conducted information. At the same time, theexamination control unit 406 transmits the reconstruction completionnotification to the display control unit 4070. Upon receipt of thereconstruction completion notification, the display control unit 4070transmits the reconstruction completion notification to the display unit109. Upon receipt of the reconstruction completion notification, thedisplay unit 109 makes the progress bar being displayed in the imagedisplay portion 1002 invisible. Then, the display unit 109 displays thetomosynthesis image as a preview in the image display portion 1002, andupdates a display annotation. On the reconstruction screen 1101,reconstruction is re-performed on the tomosynthesis image by editing thewindow processing, reproduction process, or reconstruction parameters.In this case, in the present invention, in a case where reconstructionis re-performed, the imaging control unit 405 refers to the content ofthe edited reconstruction parameters, and determines whether or not theavailability of execution of auto-window processing immediately afterreconstruction (FIG. 21). Accordingly, auto-window processing isexecuted only when necessary for the execution of reconstruction,enabling the display of a tomosynthesis image subjected to the optimumwindow processing always desired by the operator. Thereafter, uponacceptance of a reconstruction confirmation instruction, the operationunit 108 transmits the reconstruction confirmation notification to theinput detection unit 4071. Upon receipt of the reconstructionconfirmation notification, the input detection unit 4071 transmits thereconstruction confirmation notification to the examination control unit406. Upon receipt of the reconstruction confirmation notification, theexamination control unit 406 saves the tomosynthesis image. In thiscase, in the present invention, the examination control unit 406compares the tomosynthesis image for which reconstruction has beenconfirmed with the tomosynthesis image which are already present in theimaging technique information in terms of the reconstruction parametersand the image processing parameters, and judges whether or not thetomosynthesis image can be saved (FIG. 23). This can prevent a pluralityof completely identical tomosynthesis images from being saved. At thesame time as this, when tomosynthesis images are displayed in parallelon the imaging screen 1001, the issue of an effect of the arrangement ofidentical tomosynthesis images on medical interpretation can beaddressed.

<Correspondence Correction Process>

The details of the correspondence correction process will be describedhereinafter with reference to FIG. 17 and FIG. 18.

The process of the correspondence correction unit 1601 will be describedwith reference to FIG. 17. This process is another embodiment of thecorrection process in step S1307 in FIG. 13. FIG. 17 illustrates anexample in which a discrepancy occurs between the number of projectedimage frames and the number of pieces of position information. Ingeneral, when projected images are captured, as illustrated in FIG. 17,the X-ray control unit 104 and the X-ray detector 106 notify the imagingcontrol device 107 of position information which is synchronized withthe reading of image data over a period from the start of imaging to theend of imaging. Thus, no discrepancy occurs between the number of framesof projected images and the number of pieces of position information.However, due to reasons such as an operational control error of theapparatus, as illustrated in FIG. 17, there may be a discrepancy withthe number of frames of projected images. FIG. 17 illustrates, by way ofexample, the case where the number of pieces of position information islarger than expected, and all the patterns of discrepancies between thenumber of frames of projected images and the number of pieces ofposition information are included. In this case, there is a problem inthat a reconstruction process with a discrepancy between the number offrames of projected images and the number of pieces of positioninformation may cause an error. Thus, as in FIG. 17, if there is adiscrepancy between the number of frames of projected images and thenotified number of pieces of position information, a correction processfor making the number of frames of projected images and the notifiednumber of pieces of position information match each other is performedto make reconstruction available, in which state a reconstructionprocess is executed. The correction process illustrated here may be thefollowing method. Each of the pieces of image information on theprojected image frames and each of the pieces of and positioninformation have recorded therein a time at which the correspondinginformation was acquired, a projected image frame and a piece ofposition information having the same recorded time are paired, and theremaining information is discarded. Alternatively, a method may be usedin which projected image frames and pieces of position information aresequentially paired one by one from the beginning and the finalremaining information is discarded. Alternatively, a method may be usedin which projected image frames and pieces of position information aresequentially paired one by one from the end and the final remaininginformation is discarded. Alternatively, a method may be used in whichthe position information with an imaging angle of 0° or the positioninformation with an X-ray detector moving distance of 0 is aligned withthe center of the projected image frames, the projected image frames andthe pieces of position information are sequentially paired one by onetoward the beginning and end from the aligned position, and the finalremaining information is discarded. Alternatively, a method may be usedin which if the number of pieces of position information is smaller thanthe number of projected image frames, position information correspondingto the remaining projected image frame is calculated from the notifiedposition information group and is added. The correction processdescribed above enables a reconstruction process to be executed withaccuracy maintained even if there arises a problem that is not intendedby the operator, such as a discrepancy between the number of frames ofprojected images and the number of pieces of position information.

Here, an example of a pop-up screen 1801 displayed on the reconstructionscreen 1101 when the correction process is carried out in step S1315 inFIG. 13 is illustrated using FIG. 18. The pop-up screen 1801 isdisplayed on the reconstruction screen 1101. The pop-up screen 1801shows a message indicating that a correction process has been carriedout, and an OK button 1702. When the OK button 1802 is pressed, thepop-up screen 1801 is closed. The pop-up screen 1801 having theconfiguration described above is displayed.

<Display Process Taking into Account Invalid Image Area>

In the following, the details of a display process taking into accountan invalid image area will be described with reference to FIG. 19 andFIG. 20.

FIG. 19 illustrates an example of valid frames in the present invention.As illustrated in FIG. 19, tomosynthesis images in a region where theobject is included are referred to as valid frames, and the othertomosynthesis images are referred to as invalid frames. Accordingly, atomosynthesis image in which the object is not included is controlled sothat no invalid frames are displayed, enabling only the valid frames tobe displayed as previews. Thus, diagnostic accuracy is improved. Inaddition, the reproduction process does not involve the need tosuccessively specify ranges only for valid frames and reproduce thevalid frames, achieving smooth work flow. Furthermore, control isperformed to save only the valid frames, providing efficient storagecapacity. In the following, the details of the valid frame determinationprocess will be provided. In the valid frame determination process,position information notified when a projected image is captured is used(FIG. 3). Upon receipt of a reconstruction completion notification fromthe image processing unit 110, the imaging control unit 405 transmits avalid frame determination request notification to the valid framedetermination unit 1604. The valid frame determination requestnotification includes reconstruction parameters and positioninformation. Upon receipt of the valid frame determination requestnotification, the valid frame determination unit 1604 carries out avalid frame determination process. The valid frame determination processillustrated here is separated into a lower valid frame determinationprocess for determining a valid frame in the downward direction withrespect to the isocenter, and an upper valid frame determination processfor determining a valid frame in the upward direction. The lower validframe determination process may be a method for making frames above theimaging table 105 valid in accordance with the following equation.The number of lower valid frames x=isocenter-to-table-top distance/slicepitch

Alternatively, a method for making image frames included in a distancecorresponding to a certain threshold value from the isocenter valid maybe used. In this case, the threshold value may be fixed or editable.Alternatively, a method for making a number of image framescorresponding to a certain number of slices from the isocenter valid maybe used. In this case, the number of slices set as valid frames may befixed or editable. In contrast, the upper valid frame determinationprocess may be a method for making image frames included in theX-ray-source-to-object distance valid in accordance with the followingequation.The number of lower valid frames x=X-ray-source-to-object distance/slicepitch

Alternatively, a method for making image frames included in a distancecorresponding to a certain threshold value from the isocenter valid maybe used. In this case, the threshold value may be fixed or editable.Alternatively, a method for making a number of image framescorresponding to a certain number of slices from the isocenter valid maybe used. In this case, the number of slices set as valid frames may befixed or editable. Alternatively, a method for setting image framesincluded in the X-ray-source-to-object distance as valid frames may beused. Alternatively, a method for setting image frames included in thesame distance as the isocenter-to-table-top distance as valid frames maybe used.

When the valid frame determination process described above ends, thevalid frame determination unit 1604 transmits a valid framedetermination notification to the imaging control unit 405. The validframe determination notification includes a sequence of valid framenumbers. Upon receipt of the valid frame determination notification, theimaging control unit 405 inputs image information on the tomosynthesisimage to the valid frame determination notification, and transmits thevalid frame determination notification to the examination control unit406. Upon receipt of the valid frame determination notification, theexamination control unit 406 inputs valid frame information to imagingtechnique information in the held examination-scheduled-to-be-conductedinformation. Thereafter, the examination control unit 406 saves onlyvalid frame image data of the tomosynthesis image. Further, theexamination control unit 406 transmits a valid frame displaynotification to an input/output control unit 407. The valid framedisplay notification includes the image information on the tomosynthesisimage, and the sequence of valid frame numbers. Upon receipt of thevalid frame display notification, the input/output control unit 407transmits the valid frame display notification to the display unit 109.Upon receipt of the valid frame display notification, the display unit109 displays only the valid frames when displaying the targettomosynthesis image as a preview and reproducing and displaying thetarget tomosynthesis image.

In the example described above, the valid frame determination unit 1604determines valid frames, but is not limited thereto. In anotherembodiment, invalid frames are determined. As described above, a rangewithin which the object is not present, for example, a tomographic imageat a position away from the object more than from the detection surfaceof the X-ray detection unit among a plurality of tomographic images,that is, frames located in a region below the table top, is determinedas invalid frames. Alternatively, if the isocenter position is specifiedon the object, a region closer to the X-ray generation unit 102 from theisocenter position than a predetermined distance is designated as anarea outside the object, and tomographic images located in the regionare determined as invalid frames. By doing so, a result obtained byremoving unnecessary image information can be presented to the user. Inaddition, the display control unit 4070 removes image data determined tobe an invalid frame, and causes the result to be displayed on thedisplay unit 109. This makes it easy to check whether appropriateimaging is ongoing, and can provide an image suitable for diagnosis.

Here, an example of the reconstruction screen 1101 showing areproduction processing portion 2001 displayed in step S609 in FIG. 6 isillustrated using FIG. 20. In FIG. 20, the frame specifying slider 1103,which is an example of a slider display indicating the respectivepositions of a plurality of tomographic images (slices, frame images),is displayed under the control of the display control unit 4070. Thedisplay control unit 4070 causes a first region where the plurality oftomographic images are displayed to be displayed, and also causes theframe specifying slider 1103 for selecting one of the plurality oftomographic images to be displayed along the first region. The sliderdisplay is not limited to the frame specifying slider 1103 and alsoincludes the 3D slider 1122. In the example in FIG. 20, the 3D slider1122 is invisible. The display control unit 4070 may perform control todisplay the 3D slider 1122.

In the slider display, the display control unit 4070 associatesindividual positions on the slider display with a plurality oftomographic images, and specifies each position of the slider so that atomographic image corresponding to the position can be selected. Thedisplay control unit 4070 causes the selected tomographic image to bedisplayed in the image display portion 1102. The tomographic images atpositions the most away from the isocenter among a plurality oftomographic images determined by the valid frame determination unit 1604to be valid are associated with the positions of the upper and lowerends of the slider bar. The display control unit 4070 associates, forexample, the tomographic image of the valid frame the closest to theX-ray generation unit 102 with the position of the upper end, and thetomographic image of the valid frame the farthest from the X-raygeneration unit 102, for example, the tomographic image in the closestproximity to the surface of the top of the imaging table 105, with theposition of the lower end. Doing so allows the display control unit 4070to display a tomosynthesis image while removing tomographic images thatare not valid frames, or an invalid image area, to be displayed, whichcan help appropriately make a diagnosis.

Here, for example, the condition setting unit 4051 is capable of settingthe existence range of the object or the value of the thickness. The setexistence range of the object is used as the display range of atomographic image by the display control unit 4070. In addition, thevalid frame determination unit 1604 determines a frame image locatedwithin the existence range as a valid frame, and the display controlunit 4070 sets the valid frame as a display target. In another example,furthermore, the set existence range of the object is used as thegeneration range of a tomosynthesis image by the reconstructionprocessing unit 1611, and a tomosynthesis image is subjected to areconstruction process within the generation range, enabling thereconstruction process to be performed within an appropriate range,leading to a reduction in processing load. For example, the existencerange or generation range described above is two-dimensionally displayedby the frame specifying slider 1103 or is three-dimensionally displayedby the 3D slider 1122, which can appropriately help the operator.

In another exemplary embodiment, it is also possible to determine theexistence range or generation range described above in accordance withprojected images and position information on the projected images. Forexample, the imaging control unit 405 determines the existence range ofthe object on the basis of the pixel values of a reconstructedtomosynthesis image. Alternatively, similar processing can also beperformed based on the projected images. Doing so enables a tomographicimage to be generated or displayed within an appropriate range withoutforcing the operator to input object thickness information and so forth.

In the slider display described above, the upper portion of the screenis associated with a tomographic image close to the X-ray generationunit 102 and the lower portion of the screen is associated with atomographic image away from the X-ray generation unit in order tosupport the actual imaging system. However, this does not apply when theimaging system is arranged in a different way. For example, in a casewhere tomosynthesis imaging is performed with the object in a standingposition, tomographic images may be arranged in the horizontal directionfor association. In this case, for example, the frame specifying slider1103 may be displayed along a lower or upper side of the image displayportion 1102.

In the slider display described above, furthermore, the framereproduction range setting portion 1117 including a plurality of marksindicating the reproduction range of a frame is assigned by the displaycontrol unit 4070. The marks can be arranged at arbitrary positionscorresponding to tomographic images in accordance with the operationinput from the operation unit 108. The marks include, for example, afirst mark indicating the start point of the range, a second markindicating the end point of the range, and a third mark that is arrangedalways between the first and second marks. The display control unit 4070moves the third mark, thereby moving the first mark and the second markin association with the movement of the third mark with the distancebetween the third mark and the first mark and the distance between thethird mark and the second mark maintained. Accordingly, the reproductionrange can be changed.

In addition, the display control unit 4070 causes a plurality oftomographic images to be continuously displayed in sequence within therange defined by the plurality of marks in accordance with aninstruction based on the operation input to the reproduction processingportion 2001 serving as a GUI described below with reference to FIG.22(b). This enables the valid range to be automatically and continuouslydisplayed, and the user is able to concentrate on checking an imagewithout performing an operation. In addition, the reproduction rangedescribed above is specified for a valid frame. Accordingly, a validframe can be selectively reproduced and displayed.

The display control unit 4070 causes the initial position of the thirdmark to be displayed as a position corresponding to the tomographicimage at the isocenter position. This enables the user to understand theisocenter position on the basis of the initial position of the thirdmark. Note that the display control unit 4070 is also capable of causingthe isocenter position to be displayed separately from the third mark.For example, as in the 3D slider 1201 illustrated in FIG. 12, theisocenter position is represented by a cross mark.

When the reproduction process instruction portion 1119 is pressed on thereconstruction screen 1101, the 3D slider 1122 becomes invisible. Thereproduction processing portion 2001 is then displayed in the samedisplay area as that of the 3D slider 1122. The reproduction processingportion 2001 is used to perform a reproduction process on a frame imagegroup of a tomosynthesis image being displayed as a preview. Thereproduction processing portion 2001 is constituted by a loopreproduction instruction portion 2002, a reciprocal reproductioninstruction portion 2003, a range-specified reciprocal reproductioninstruction portion 2004, a frame rate editing portion 2005, a reversereproduction instruction portion 2006, a frame-by-frame backwardinstruction portion 2007, a reproduction stop instruction portion 2008,a frame-by-frame forward instruction portion 2009, and a reproductioninstruction portion 2010. The loop reproduction instruction portion 2002is a button for selecting “loop reproduction” as a reproduction method.The reciprocal reproduction instruction portion 2003 is a button forselecting, as a reproduction method, “reciprocal reproduction” forreciprocally reproducing the first frame and the last frame among allthe frames. The range-specified reciprocal reproduction instructionportion 2004 is a button for selecting “range-specified reciprocalreproduction” for reciprocally reproducing a minimum frame and a maximumframe within a range set by the frame reproduction range setting portion1117. The frame rate editing portion 2005 is a control for editing thereproduction frame rate. The set frame rate value is displayed near thecontrol. The reverse reproduction instruction portion 2006 is a buttonfor providing an instruction to start “reverse reproduction” forperforming reproduction in the direction from the last frame toward thefirst frame. When the reverse reproduction instruction portion 2006 ispressed, reverse reproduction is executed using the currently selectedreproduction method. The frame-by-frame backward instruction portion2007 is a button for providing an instruction to switch the frame imageto be displayed as a preview to the immediately preceding frame image.The display reproduction stop instruction portion 2008 is a button forproviding an instruction to stop reproduction. The button is disabledduring the stop of reproduction. The frame-by-frame forward instructionportion 2009 is a button for providing an instruction to switch theframe image to be displayed as a preview to the immediately subsequentframe image. The reproduction instruction portion 2010 is a button forproviding an instruction to start “reproduction” for performingreproduction in the direction from the first frame toward the lastframe. When the reproduction instruction portion 2010 is pressed,reproduction is executed using the currently selected reproductionmethod. In the case of reverse reproduction and reproduction, only thevalid frames are reproduced and displayed. For a tomosynthesis imageframe which can be specified by a frame-by-frame forward orframe-by-frame backward operation, similarly, only the valid frames canbe specified. The reconstruction screen 1101 showing the reproductionprocessing portion 2001 having the configuration described above isdisplayed. The configuration and display form of the reproductionprocessing portion 2001 in the present invention are not limitedthereto.

In the embodiment, both a process for determining a valid or invalidimage area from a tomosynthesis image generated in advance and a processfor determining a valid or invalid image area in accordance withposition information or the like in advance before a tomosynthesis imageis generated are also included. In the case of determination in advancebefore the generation of a tomosynthesis image, first of all, it isconvenient to control setting information for setting a generationrange. The condition setting unit 4051 sets at least one condition amongthe generation pitch of a plurality of tomographic images, the number oftomographic images generated, and the generation range of atomosynthesis image. In this case, in response to one of the conditionsbeing set, the condition setting unit 4051 limits the range over whichthe other conditions can be set. For example, the generation pitch isset to a certain value. In this case, if too many tomographic images arecaptured, the imaging range becomes too large. Thus, an upper limit isimposed on the number of captured images as far as a threshold valuerelated to the object thickness is not exceeded. Alternatively, thegeneration range described above is provided with a cap in advance. Inaddition, the generation range is controlled so as to be set within arange above the table top. Doing so can reduce the probability that aninappropriate generation range may be set by the operator, and enablesan appropriate tomosynthesis image to be generated.

<Control as to Whether to Execute Tone Conversion Processing>

Next, a process flow related to window processing from an execution of areconstruction process in step S609 in FIG. 6 until a tomosynthesisimage is displayed is illustrated using FIG. 21. In the illustratedprocess, first, the reconstruction processing unit 1611 reconstructs afirst tomosynthesis image from the plurality of projected images inaccordance with the reconstruction conditions (the previousreconstruction in step S2102). The tone conversion parameter acquisitionunit 1612 acquires tone conversion conditions on the basis of thereconstructed tomosynthesis image. In this state, the condition settingunit 4051 is capable of setting reconstruction conditions or toneconversion conditions in accordance with the operation input to theoperation unit 108. The settings described above are executed, andprocess flows when the process conditions described above are changedand not changed are illustrated in steps after step S2101. When thesettings of the reconstruction conditions are changed, thereconstruction processing unit 1611 reconstructs a second tomosynthesisimage in accordance with the reconstruction conditions after the change.Then, the imaging control unit 4051 controls whether or not to execute,for the second tomosynthesis image, tone conversion processing(auto-window processing) using tone conversion conditions obtainedthrough the analysis process of the tone conversion parameteracquisition unit 1612 in accordance with the second tomosynthesis image.

When the condition setting unit 4051 changes the reconstructionconditions and the tone conversion conditions, the imaging control unit405 controls whether or not to use the tone conversion conditions afterthe change for tone conversion processing for a tomosynthesis imagereconstructed in accordance with the reconstruction conditions after thechange. In a different aspect, the imaging control unit 405 controlswhether or not to execute tone conversion processing on a tomosynthesisimage, which is reconstructed in accordance with the reconstructionconditions after the change, using the tone conversion conditionsobtained through the analysis process of the tone conversion parameteracquisition unit on the basis of the tomosynthesis image.

First, in step S2101, a reconstruction process is carried out. In thepresent invention, the reconstruction process can be executed not onlyimmediately after the capture of projected images described above butalso when the reconstruction process instruction portion 1010 on theimaging screen 1001 is pressed and when the reconstruction processinstruction portion 1115 on the reconstruction screen 1101 is pressed.Upon receipt of an instruction for the reconstruction process from thereconstruction process instruction portion 1010 on the imaging screen1001 or the reconstruction process instruction portion 1115 on thereconstruction screen 1101, the operation unit 108 transmits areconstruction request notification to the input/output control unit407. Upon receipt of the reconstruction request notification, theinput/output control unit 407 transmits the reconstruction requestnotification to the examination control unit 406. In this case, if aninstruction has been received through the reconstruction processinstruction portion 1115 on the reconstruction screen 1101, theinput/output control unit 407 receives reconstruction parameters inputto the reconstruction screen 1101 being displayed from the display unit109, and inputs the reconstruction parameters to the reconstructionrequest notification before transmitting the reconstruction requestnotification. Upon receipt of the reconstruction request notification,the examination control unit 406 inputs preview-selection imageinformation and image data to the reconstruction request notification,and then transmits the reconstruction request notification to theimaging control unit 405. In this case, regardless of the imaging typeof preview-selection image, a projected image of an imaging techniqueincluding the preview-selection image is input as image data. Thisenables a reconstruction process to be started in any case. In addition,the imaging control unit 405 checks whether or not the reconstructionrequest notification received from the examination control unit 406includes reconstruction parameters. If no reconstruction parameters areincluded, the imaging control unit 405 receives the input of defaultreconstruction parameters in the imaging technique information. The flowfrom when the imaging control unit 405 transmits a reconstructionrequest notification to the image processing unit 110 until areconstruction process is executed is similar to that of step S608 tostep S609 in FIG. 6. At the same time of transmitting a reconstructionrequest notification to the image processing unit 110, the imagingcontrol unit 405 transmits an auto-window execution determinationnotification request to the tone conversion processing executiondetermination unit 1608. The auto-window execution determination requestnotification includes image information on projected images,reconstruction parameters, and window adjustment execution informationobtained after the previous reconstruction process. The tone conversionprocessing execution determination unit 1608 holds image information onprojected images and reconstruction parameters for which the previousreconstruction process has been executed.

In step S2102, in accordance with receipt of the auto-window executiondetermination request notification, the tone conversion processingexecution determination unit 1608 compares the projected imagessubjected to the reconstruction process with the projected images usedfor the previously executed reconstruction process, and determineswhether or not both images are identical. If both images are different,the tone conversion processing execution determination unit 1608 setsthe auto-window processing execution availability to “available”, andthen transmits an auto-window execution determination notification tothe imaging control unit 405. The auto-window execution determinationnotification includes the auto-window processing execution availability.

If both images are identical, in step S2103, the tone conversionprocessing execution determination unit 1608 checks whether or not theoperator has performed window adjustment after the execution of theprevious reconstruction process. The tone conversion processingexecution determination unit 1608 checks the window adjustment executioninformation obtained after the previous reconstruction process. If theoperator has executed window adjustment, the tone conversion processingexecution determination unit 1608 sets the auto-window processingexecution availability to “unavailable”. Thereafter, the tone conversionprocessing execution determination unit 1608 transmits the auto-windowexecution determination notification to the imaging control unit 405.

Here, the imaging control unit 405 controls whether or not to use thetone conversion conditions after the change in accordance with whetheror not a tomosynthesis image based on the reconstruction conditions andtone conversion processing conditions before the change has beengenerated. That is, if no tomosynthesis image based on a projected imagegroup corresponding to the same imaging technique has been generated,auto-window processing based on the analysis process of the toneconversion parameter acquisition unit 1612 is executed. This processimplements, for example, automatic control for executing auto-windowprocessing in step S2102 and step S2106 in accordance with thecompletion of the capture of projected images.

If the tomosynthesis image has been generated, further through theprocess subsequent to step S2103, in step S2107, tone conversionprocessing that inherits the previous window values (the tone conversionconditions after the change) is executed on a tomosynthesis imagereconstructed under the reconstruction conditions after the change. Thisenables appropriate control of the generation of a tomosynthesis image.

If the operator has executed window adjustment, the tone conversionprocessing execution determination unit 1608 performs a process fromstep S2104 to check the content of the change of the reconstructionconditions. The tone conversion processing execution determination unit1608 compares the reconstruction parameters used for the execution ofthe previous reconstruction with the reconstruction parameters includedin the auto-window execution determination notification request, interms of the parameter values of the reconstruction method, the filtertype, the filter DC, the cutoff frequency, and the noise reductionprocess. The reconstruction parameters illustrated here include therespective values of the portions from the reconstruction methodselection portion 1108 to the noise reduction process editing portion1114 on the reconstruction screen 1101.

Then, in step S2105, the tone conversion processing executiondetermination unit 1608 checks the comparison results for all theacquired parameter values. As a result, if even one parameter differs,the tone conversion processing execution determination unit 1608 setsthe auto-window processing execution availability to “available”. If thevalues of all the parameters are identical, the tone conversionprocessing execution determination unit 1608 sets the auto-windowprocessing execution availability to “unavailable”. Thereafter, the toneconversion processing execution determination unit 1608 transmits anauto-window execution determination notification to the imaging controlunit 405. Upon receipt of the auto-window execution determinationnotification, the imaging control unit 405 checks the auto-windowprocessing execution availability. If the auto-window processingexecution availability indicates “available”, the imaging control unit405 transmits an auto-window processing request notification to theimage processing unit 110. The auto-window processing requestnotification includes image data and image information on atomosynthesis image to be subjected to auto-window processing. If theauto-window processing execution availability indicates “unavailable”,the imaging control unit 405 transmits a window processing requestnotification to the image processing unit 110. The window processingrequest notification includes image data and image information on atomosynthesis image to be subjected to auto-window processing.

Upon receipt of the auto-window processing request notification, in stepS2106, the image processing unit 110 executes auto-window processing onthe target tomosynthesis image data. Thereafter, the image processingunit 110 inputs the values of the window level and the window widthcalculated in the auto-window procedure to the image information, andthen transmits a window processing result notification to the imagingcontrol unit 405.

Upon receipt of the window processing request notification, in stepS2107, the image processing unit 110 executes window processing on thetarget tomosynthesis image data using the values of the window level andthe window width input to the image information. Thereafter, the imageprocessing unit 110 transmits a window processing result notification tothe imaging control unit 405.

Then, in step S2108, the generated tomosynthesis image is displayed.Upon receipt of both the reconstruction completion notification and thewindow processing notification from the image processing unit 110, theimaging control unit 405 transmits a reconstruction completionnotification to the examination control unit 406. Thereafter, theexamination control unit 406 adds the newly generated tomosynthesisimage information to an imaging technique for which reconstruction hasbeen completed within the imaging technique information included in theexamination-scheduled-to-be-conducted information. At the same time, theexamination control unit 406 transmits the reconstruction completionnotification to the input/output control unit 407. Upon receipt of thereconstruction completion notification, the input/output control unit407 transmits a reconstruction completion notification to the displayunit 109. Upon receipt of the reconstruction completion notification,the display unit 109 makes the progress bar being displayed in the imagedisplay portion 1002 invisible. Then, the display unit 109 displays thetomosynthesis image as a preview in the image display portion 1002, andupdates a display annotation.

Through the process described above, in the present invention, when areconstruction process is executed, it is possible to determine theavailability of the execution of auto-window processing in accordancewith the content of the edited reconstruction parameters. This enablesauto-window processing to be executed and a tomosynthesis image to bedisplayed with the optimum density when a new tomosynthesis image isgenerated or in the case of a reconstruction process which involveschanges in density. In addition, if the operator has performed editingto the desired window values or in the case of an image constructionprocess which does not involve changes in density, the window values areinherited, thereby achieving the advantage of it being possible todisplay a tomosynthesis image in a state that is always suitable formedical interpretation.

In a different aspect, the tone conversion parameter acquisition unit1612 acquires a first tone conversion condition, and the conditionsetting unit 4051 sets a second tone conversion condition different fromthe first tone conversion condition and also sets a secondreconstruction condition different from a first reconstruction conditionset in advance. In this situation, the imaging control unit 405 controlswhich of the first tone conversion condition and the second toneconversion condition to use for tone conversion processing to beperformed on a tomosynthesis image reconstructed in accordance with thesecond reconstruction condition, in accordance with the firstreconstruction condition and the second reconstruction condition. Bydoing so, even if the operator has actively set tone conversionconditions (second tone conversion condition), a process based on a toneconversion condition (first tone conversion condition) different fromthe tone conversion conditions is performed in accordance with thesituation, enabling an appropriate tomosynthesis image to be obtained inaccordance with the situation.

In another embodiment, the imaging control unit 405 performs thefollowing process if one of the reconstruction conditions, for example,the reconstruction method, the filter settings, and the noise processingparameter, has been changed. That is, the imaging control unit 405causes tone conversion processing to be executed in accordance with toneconversion conditions obtained through the analysis process of the toneconversion parameter acquisition unit 1612 from a tomosynthesis imagereconstructed in accordance with the reconstruction method after thechange. Accordingly, if the reconstruction parameters have been changed,it is judged that it is inappropriate to use the window processingconditions set by the reference to a tomosynthesis image reconstructedunder the reconstruction conditions before the change, and auto-windowprocessing is executed.

In another embodiment, the reconstruction method, the filter settings,and the noise processing parameter in the reconstruction conditions arenot changed but the reconstruction pitch, the number of reconstructedimages, or the reconstruction range has been changed. In this case, theimaging control unit 405 causes the tone conversion processing unit 1613to execute tone conversion processing in accordance with the toneconversion conditions after the change. Unless the reconstruction methodor the like is changed, an obtained image is considered to besubstantially similar to an image before the change. Accordingly, toneconversion processing is performed using tone conversion conditionsinput by the operator actively operating the operation unit 108,enabling a tomosynthesis image to be displayed with the tone desired bythe operator. In this case, furthermore, the imaging control unit 405performs control not to cause the tone conversion parameter acquisitionunit 1612 to execute an analysis process for acquiring tone conversionconditions in accordance with the content of the change of thereconstruction conditions, thereby achieving efficient processing.

In another embodiment, after automatic generation control of the firsttomosynthesis image described above and the process for generating asecond tomosynthesis image, in accordance with the operation input, theimaging control unit 405 causes the reconstruction of a tomosynthesisimage based on a plurality of projected images described above to bere-executed in accordance with the operation input. For example, thecondition setting unit 4051 changes the setting of process conditionssuch as reconstruction conditions or tone conversion conditions, asappropriate, to generate a different tomosynthesis image, resulting in atomosynthesis image more suitable for diagnosis being obtained.

In addition, in a case where a different reconstruction method (secondreconstruction method) is set by the condition setting unit 4051 afterthe automatic control described above, even if the condition settingunit 4051 has set a different tone conversion condition, a tomosynthesisimage obtained through the reconstruction re-executed in step S2107 issubjected to tone conversion processing based on the first toneconversion condition.

Here, an example of the reconstruction screen 1101 showing a windowadjustment portion 2201 displayed in step S609 in FIG. 6 is illustratedusing FIG. 22. When the window adjustment display instruction portion1118 is pressed on the reconstruction screen 1101, the 3D slider 1122becomes invisible. Then, the window adjustment display unit 2201 isdisplayed in the same display area as that of the 3D slider 1122. Thewindow adjustment portion 2201 is a control for adjusting window valuesfor a tomosynthesis image being displayed as a preview. The windowadjustment portion 2201 is constituted by a window level editing portion2202, a window width editing portion 2203, an auto-window processinginstruction portion 2204, and a window value reset instruction portion2205. The window level editing portion 2202 is a control for editing thewindow level for the tomosynthesis image being displayed as a preview.Changing the value displayed in the edit box or dragging the mouse onthe image display portion 1102 applies the editing to the image beingdisplayed as a preview. The window width editing portion 2203 is acontrol for editing the window width for the tomosynthesis image beingdisplayed as a preview. Changing the value displayed in the edit box ordragging the mouse on the image display portion 1102 applies the editingto the image being displayed as a preview. The auto-window processinginstruction portion 2204 is a button for providing an instruction toperform auto-window processing to calculate the optimum values of thewindow level and the window width for the image data by using the imageprocessing unit 110 and to automatically apply the values to thetomosynthesis image currently being selected as a preview. When thebutton is pressed, the frame image being displayed as a preview issubjected to an auto-window processing. The window value resetinstruction portion 2205 is a button for providing an instruction toperform a window value reset process for returning the values of thewindow level and the window width to the initial values immediatelyafter reconstruction. The reconstruction screen 1101 showing the windowadjustment portion 2201 having the configuration described above isdisplayed. The configuration and display form of the window adjustmentportion 2201 in the present invention are not limited thereto.

In a different aspect, in the exemplary embodiment described above, theimaging control unit 405 automatically performs a reconstruction processand auto-window processing in accordance with the completion of thecapture of projected images, and performs control to cause the displayunit to display the tomosynthesis image subjected to the auto-windowprocessing. That is, the reconstruction processing unit 1611 starts thereconstruction of a tomosynthesis image in accordance with the captureof projected images under the control of the imaging control unit 405.The tone conversion parameter acquisition unit 1612 starts an analysisprocess for the tomosynthesis image in accordance with the completion ofthe reconstruction, and acquires tone conversion conditions. The toneconversion processing unit 1613 executes tone conversion processing inaccordance with the completion of the reconstruction and the completionof the analysis process. The automatic control described above canreduce operation input, and enables the imaging apparatus to efficientlyobtain a tomosynthesis image. In a case where the image processing unit110 is to generate slice images from the tomosynthesis image serving asthree-dimensional volume data and to perform tone conversion processing,the slice images may be subjected to an analysis process and toneconversion processing in parallel to the sequential generation of theslice images by using the image processing unit 110. In this case, forexample, it is effective that a slice image be generated from theisocenter position and the slice image at the isocenter position beanalyzed to obtain tone conversion conditions.

The advantages of the processes according to the embodiment describedabove will be described. In a case where auto-window processing is to beexecuted automatically, for example, window values edited on purpose maybe changed by a user as desired, which would cause an increase in timeand labor for an operator to re-edit the window values. Accordingly, ina process according to one embodiment, in the reconstruction and displayof a tomosynthesis image, the auto-window execution availability isjudged in accordance with the reconstruction parameters used for theprevious reconstruction and the content of the editing of the windowvalues, thereby reducing the load imposed on the operator due to thewindow adjustment. In addition, in the reconstruction and display of atomosynthesis image, the auto-window execution availability is judged inaccordance with the reconstruction parameters used for the previousreconstruction and the content of the editing of the window values. Thisenables a tomosynthesis image to be displayed with the window valuesdesired by the operator. In addition, the load imposed on an operatorinvolved in window adjustment can be reduced.

<Additional Display Control of Icon>

Next, a process flow from the confirmation of reconstruction in stepS609 in FIG. 6 until an image is displayed as a preview is illustratedusing FIG. 23. Here, the examination control unit 406 controls, inaccordance with set process conditions and the process conditionscorresponding to a tomosynthesis image already generated by the imageprocessing unit 110, whether or not to cause the display unit to displaya new icon corresponding to the set process conditions. This can reducethe probability of any redundant icon being displayed, and allows a userto easily select a tomosynthesis image suitable for diagnosis.

Additional display control of an icon according to one embodiment willbe described. First, in step S2301, upon acceptance of a reconstructionconfirmation instruction, the operation unit 108 transmits areconstruction confirmation notification to the input/output controlunit 407. The reconstruction confirmation notification includes imageinformation. Upon receipt of the reconstruction confirmationnotification, the input/output control unit 407 transmits thereconstruction confirmation notification to the examination control unit406.

Then, in step S2302, upon receipt of the reconstruction confirmationnotification, the examination control unit 406 checks whether thetomosynthesis image is present in the same tomosynthesis imagingtechnique. If the tomosynthesis image is not present in the sametomosynthesis imaging technique in step S2302, the examination controlunit 406 saves the tomosynthesis image. The condition comparison unit1602 determines whether or not at least any one of the set processconditions matches the corresponding one of the process conditionscorresponding to a tomosynthesis image already generated by the imageprocessing unit 110.

Then, in step S2310, a new captured image thumbnail 1011 is added to theimaging technique display portion 1009 on the imaging screen 1001. Theexamination control unit 406 transmits a thumbnail image additionnotification to the input/output control unit 407. The thumbnail imageaddition notification includes thumbnail image data, imaging techniqueinformation, thumbnail addition position information, and a similargroup number. The thumbnail addition position information described hererepresents a number for judging where a thumbnail is to be added in theimaging technique display portion 1009 in which items are to be added.The similar group number described here is a number that identifies asimilar group to which the tomosynthesis image belongs in an imagingtechnique. In step S2310, the examination control unit 406 inputs thebottommost number in the imaging technique to thumbnail additionposition information. Further, the examination control unit 406 inputs anew, unused number in the imaging technique as a similar group number.Upon receipt of the thumbnail image addition notification, theinput/output control unit 407 transmits the thumbnail image additionnotification to the display unit 109. Upon receipt of the thumbnailimage addition notification, the display unit 109 displays an additionalthumbnail image at a designated location in accordance with the imagingtechnique information and the thumbnail addition position information.Thereafter, the display unit 109 transmits a thumbnail image additioncompletion notification to the input/output control unit 407. Thethumbnail image addition completion notification includes imageinformation. Upon receipt of the thumbnail image addition completionnotification, the input/output control unit 407 transmits the thumbnailimage addition completion notification to the examination control unit406. Then, in step S2313, the newly added tomosynthesis image isdisplayed as a preview. Upon receipt of the thumbnail image additioncompletion notification to the examination control unit 406, a processfor displaying the newly added tomosynthesis image as a preview isexecuted. Then, the process ends. If the tomosynthesis image is presentin the same tomosynthesis imaging technique in step S2302, then in stepS2303, the examination control unit 406 acquires image information onall the tomosynthesis images present in the same tomosynthesis imagingtechnique. Then, in step S2304, the examination control unit 406acquires a piece of image information from the acquired tomosynthesisimage information group. Then, in step S2305, the examination controlunit 406 compares the acquired tomosynthesis image information withtomosynthesis image information for which reconstruction has beenconfirmed in terms of all the parameter values included in thereconstruction parameters and the image processing parameters. Then, instep S2306, if both pieces of tomosynthesis image information areidentical in terms of all the parameters, the examination control unit406 does not save a tomographic image for which reconstruction has beenconfirmed.

Then, in step S2314, the examination control unit 406 inherits the imagedisplayed as a preview before the execution of the reconstructionprocess, and then the process ends. In the manner described above, if atomosynthesis image generated under process conditions that areidentical to the set process conditions is present, the examinationcontrol unit 406 is configured not to execute a tomosynthesis imagegeneration process based on the set process conditions or icon additioncontrol. This can prevent an increase in the number of unnecessaryicons.

If both pieces of tomosynthesis image information are different in termsof all the parameters in step S2306, then in step S2307, the examinationcontrol unit 406 checks whether comparison has been made for all thetomosynthesis images. If there is any tomosynthesis image for which nocomparison process has been made in step S2307, the process returns tostep S2304 and the processes up to step S2307 are repeatedly performed.If a comparison process has been performed for all the tomosynthesisimages in step S2307, the examination control unit 406 judges that atomosynthesis image for which reconstruction has been confirmed is notpresent in the imaging technique. Then, in step S2308, the examinationcontrol unit 406 saves the tomosynthesis image for which reconstructionhas been confirmed.

Then, in step S2309, the examination control unit 406 checks whether atomosynthesis image having the same image processing parameter ispresent in the same imaging technique as that of the saved tomosynthesisimage. If a tomosynthesis image having the same image processingparameter is not present in step S2309, the examination control unit 406executes the process after step S2310 described above. If atomosynthesis image having the same image processing parameter ispresent in step S2309, the examination control unit 406 acquires thesimilar group number and thumbnail addition position information of thetomosynthesis image at the bottommost position among a tomosynthesisimage information group having the same image processing parameter.

Then, in step S2311, the examination control unit 406 adds a newcaptured image thumbnail 1011 to the imaging technique display portion1009 on the imaging screen 1001. The examination control unit 406transmits a thumbnail image addition notification to the input/outputcontrol unit 407. In step S2311, the examination control unit 406 inputsthe respective values acquired in step S2309 to the thumbnail additionposition information and the similar group number. Upon receipt of thethumbnail image addition notification, the input/output control unit 407transmits the thumbnail image addition notification to the display unit109. Upon receipt of the thumbnail image addition notification, thedisplay unit 109 additionally displays the captured image thumbnail 1011at a designated location in accordance with the imaging techniqueinformation and the thumbnail addition position information. The displayunit 109 further displays in the newly added captured image thumbnail1011 a similarity mark corresponding to the similar group number.Thereafter, the display unit 109 transmits a thumbnail image additioncompletion notification to the input/output control unit 407. Thethumbnail image addition completion notification includes imageinformation. Upon receipt of the thumbnail image addition completionnotification, the input/output control unit 407 transmits the thumbnailimage addition completion notification to the examination control unit406. Then, in step S2313, the newly added tomosynthesis image isdisplayed as a preview. Upon receipt of the thumbnail image additioncompletion notification to the examination control unit 406, a processfor displaying the newly added tomosynthesis image as a preview isexecuted. Then, the process ends.

In the process described above, if reconstruction conditions differentfrom the reconstruction conditions corresponding to a tomosynthesisimage already generated by the image processing unit 110 have been set,the display control unit 4070 causes the display unit to display a newicon corresponding to the set reconstruction conditions (S2310).Specifically, the display control unit 4070 causes the captured imagethumbnail 1011 that is an icon corresponding to the new reconstructionconditions to be added to a display area of the imaging techniquedisplay portion 1009. The captured image thumbnail 1011 is selectable inaccordance with the operation input of the operation unit 108, and, inaccordance with selection, the display control unit 4070 causes atomosynthesis image corresponding to the captured image thumbnail 1011to be displayed. In the manner described above, the generation of a newicon allows a user to easily compare a plurality of tomosynthesisimages.

This is not to be taken in a limiting sense. In another exemplaryembodiment, a situation is considered in which the condition settingunit 4051 sets image processing conditions such as reconstructionconditions and tone conversion conditions of a tomosynthesis image inaccordance with a confirmation button 1211 being pressed in step S2301.In this situation, the following process is performed if the samereconstruction conditions as the reconstruction conditions correspondingto a tomosynthesis image already generated by the image processing unit110 have been generated and if different image processing conditionshave been set. In this case, the display control unit 4070 causes thedisplay unit to display a new icon corresponding to the set processconditions. This enables a user to easily compare a plurality of piecesof tomosynthesis image data having different image processing conditionsby using single-view display in FIG. 24(a) or multi-view display in FIG.24(b). Accordingly, more appropriate image processing conditions can bespecified.

In this case, furthermore, that is, in a case where the samereconstruction conditions as the reconstruction conditions correspondingto an already generated tomosynthesis image and different imageprocessing conditions have been set, an image processing unit 110according to one exemplary embodiment is configured to generate a newtomosynthesis image. Specifically, a plurality of tomosynthesis imageshaving different image processing conditions and having the samereconstruction conditions are saved in memory regions reserved atdifferent positions on a memory. Doing so can increase the speed of thedisplay process of a tomosynthesis image, and can facilitate easiercomparison.

In another exemplary embodiment, in a case where the same reconstructionconditions as the reconstruction conditions corresponding to an alreadygenerated tomosynthesis image and different image processing conditionshave been set, the following process is executed. That is, theexamination control unit 406 is configured to save the tomosynthesisimage and the plurality of image processing conditions in theexamination information storage unit 403 in association with each otherwithout generating a new tomosynthesis image. The saved tomosynthesisimage may be an image that has been processed under one image processingcondition among a plurality of image processing conditions. The use ofan image that has not been processed under any image processingcondition may result in the later image processing being simple. Inaccordance with the user selecting a captured image thumbnail 1011, theimage processing unit 110 performs image processing on the savedtomosynthesis image in accordance with the image processing conditionscorresponding to the thumbnail 1011 selected for the tomosynthesisimage. The tomosynthesis image subjected to the image processing isdisplayed in the image display portion 1102 or the like by the displaycontrol unit 4070. Alternatively, as in the exemplary embodimentdescribed above, each of a plurality of captured image thumbnails 1011corresponding to tomosynthesis images is constituted by an imagesubjected to image processing under the corresponding image processingconditions, enabling images to be compared by using the captured imagethumbnails 1011.

Image processing conditions for a tomosynthesis image corresponding toeach of the thumbnail images 1011 described above can be optionallychanged by the condition setting unit 4051 in accordance with theoperation input of the operation unit 108. In addition, an operationinput corresponding to an instruction for returning the changed imageprocessing conditions to the image processing conditions before thechange is defined, and the input detection unit 4071 detects this input,thus making it possible to easily return the changed image processing tothe original one. The operation input corresponding to an instructionfor returning to the image processing conditions before the change maybe, for example, an input for selecting a button on the screen, or maybe an input for pressing any button on the keyboard.

Here, an example of the single-view display and multi-view display ofthe imaging screen 1001 when the tomosynthesis image displayed in stepS2312 and step S2313 in FIG. 23 is selected as a preview is illustratedusing FIG. 24. Captured image thumbnails 1011 respectively correspondingto projected images and a tomosynthesis image for which an additioninstruction has been given are displayed in the imaging techniquedisplay portion 1009 for the tomosynthesis imaging technique. Further,each of the captured image thumbnails 1011 of images obtained bytomosynthesis imaging has displayed thereon a similarity mark 2401. Theform of the similarity mark is not limited so long as each group ofsimilar tomosynthesis images is distinguishable from the other groups.While the single-view instruction portion 1004 is selected, the imagedisplay portion 1002 provides a single-view display illustrated in FIG.24(a). While the multi-view instruction portion 1005 is selected, theimage display portion 1002 provides a multi-view display illustrated inFIG. 24(b). In the multi-view display, X-ray images or tomosynthesisimages corresponding to all the captured image thumbnails 1011 includedin the examination being conducted are displayed in parallel in theimage display portion 1002. Each of the images displayed in parallel hasdisplayed thereon an imaging type mark, a similarity mark 2401, and areject mark 2701. As in the present invention, parallel display ofimages in each similar group enables the operator to easily compare andrefer to a plurality of tomosynthesis images, making an improvement indiagnostic accuracy feasible.

As in FIG. 24(a) and FIG. 24(b) described above, the display controlunit 4070 assigns an identical mark to a plurality of iconscorresponding to the same or similar reconstruction conditions for thecaptured image thumbnails 1011 or tomosynthesis images in the multi-viewdisplay. This can facilitate the identification of tomosynthesis imagescorresponding to the same reconstruction conditions.

It is assumed here that the display control unit 4070 assigns anidentical mark to icons for images not only under the samereconstruction conditions but also under reconstruction conditions forwhich only some of the parameters are changed. For example, if thereconstruction method and the like are the same and only thereconstruction pitch, the number of tomographic images, or thegeneration range of a tomosynthesis image is changed or the noisereduction parameter is changed by only a small amount, the examinationcontrol unit 406 determines that the reconstruction conditions aresimilar.

Additionally, the display control unit 4070 may take a variety of formsof display by group. For example, tomosynthesis images included in thesame or similar reconstruction conditions are displayed side by side ina row. Alternatively, tomosynthesis images included in the same orsimilar reconstruction conditions are surrounded by a frame. Suchdisplay of a plurality of icons grouped by each of the reconstructionconditions facilitates comparison between reconstruction conditions orcomparison of image processing conditions under the same reconstructionconditions.

In another example, furthermore, the grouping described above can beselectively performed based on a variety of kinds of information. Forexample, the display control unit 4070 performs the following operation.In response to any one of the reconstruction conditions and the imageprocessing conditions being selected in accordance with the operationinput to the operation unit 108, the display control unit 4070 performsgrouping by the selected one condition, and provides display in theabove-described form indicating grouping.

In another embodiment, furthermore, the condition setting unit 4051 iscapable of performing a setting of a reject for each group for which thereconstruction conditions or image processing conditions described aboveare identical. Selecting such a group on the imaging screen 1001 andpressing the reject button 1029 allow tomosynthesis images included inthe group to be collectively set as rejects, and facilitate theoperation.

As in FIG. 24(a) described above, a GUI (1013, 1014) for performingwindow adjustment for image processing may be displayed on the imagingscreen 1001, but is not limited thereto. That is, the display controlunit 4070 is configured to display window adjustment only on thereconstruction screen 1101 so that image processing conditions areadjusted through the reconstruction screen 1101, which is displayed soas to be switchable with the imaging screen 1001. The display controlunit 4070 does not provide the display on the imaging screen 1001.Furthermore, the examination control unit 406 is capable of performing adisplay setting to set whether or not it is possible to make a change tothe image processing conditions for a tomosynthesis image generatedunder the set image processing conditions through the first screen onthe imaging screen 1001 in accordance with the operation input of theoperation unit. This can make the image processing executable asappropriate in accordance with the situation.

Here, consideration is further given of a case where the examinationcontrol unit 406 performs a setting so that a change in image processingis not available on the imaging screen 1001. If the same reconstructionconditions as the reconstruction conditions corresponding to atomosynthesis image already generated by the image processing unit 110and different image processing conditions are set, the display controlunit 4070 causes the display unit to display a new icon corresponding tothe set process conditions. In this case, image processing is executedthrough the reconstruction screen 1101. Accordingly, a new capturedimage thumbnail 1011 is displayed, enabling tomosynthesis images to becompared by different image processing conditions.

In addition to this, for example, in a case where the examinationcontrol unit 406 has performed a setting so that a change in imageprocessing is available on the imaging screen 1001, if the samereconstruction conditions as the reconstruction conditions correspondingto a tomosynthesis image already generated by the image processing unit110 and different image processing conditions are set, the followingprocess is executed. That is, the display control unit 4070 does notcause the display unit to display a new icon corresponding to the setprocess conditions. This implies that, if a change in image processingis available on the imaging screen 1001, no new captured image thumbnail1011 is generated. In this case, the image processing conditions areadjusted by using the GUI displayed on the imaging screen 1001, such asthe window level editing portion 1013 and the window width editingportion 1014. This provides the advantage of reducing the number ofcaptured image thumbnails 1011 and facilitating comparison.

In another embodiment, the examination control unit 406 controls whetheror not the image processing unit 110 generates a new tomosynthesis imagein accordance with information on the slice pitch included in the setprocess conditions. For example, consideration is given to the casewhere the set process conditions include a first reconstruction method,a first slice pitch value, and a first number of slices. In this case,furthermore, a tomosynthesis image corresponding to process conditionsincluding the first reconstruction method, the first slice pitch value,and a second number of slices larger than the first number of slices hasalready been generated. In this case, the following process is executed.That is, the examination control unit 406 does not generate atomosynthesis image based on the set process conditions. In the mannerdescribed above, if a setting is made to obtain a tomosynthesis imagehaving the same reconstruction method, the same slice pitch, and a smallnumber of slices, a tomosynthesis image including the tomosynthesisimage described above as a subset has already been generated. Thus, aprocess for generating a new tomosynthesis image is not performed or nocaptured image thumbnail is added to the imaging screen 1001. This canreduce the generation of an unnecessary tomosynthesis image, and canalso facilitate comparison between tomosynthesis images.

In the example described above, a process for comparing a plurality oftomosynthesis images generated from one projected image group has beendescribed, but is not limited thereto. For example, for the comparisonof a plurality of tomosynthesis images generated from a plurality ofprojected image groups, processes such as icon addition control anddisplay by group may be executed.

The advantages of the above-described processes according to theembodiment will be described. In a case where the number of slices andthe slice pitch are specified for the reconstruction of a tomosynthesisimage, the target is mainly a microsclere in the orthopedic region or alesion region in the body, and it is generally difficult to check thethickness of the region of interest. For this reason, it is difficult todecide on the accurate slice pitch and the accurate number of slices.Consequently, a sufficient number of slices are specified to ensure thata tomosynthesis image is reconstructed so that the region of interest isincluded in a frame group of the tomosynthesis image. In this case, itis probable that the reconstructed tomosynthesis image includes an imagenot including information on the region of interest. Such an image framenot including the region of interest is displayed side by side with animage frame including the region of interest, which may affect theaccuracy of medical interpretation. In addition, an unnecessary imageframe is also saved, causing a problem in that an amount of the storagecapacity is uselessly consumed. Meanwhile, in a case where an operatorselects and saves only a necessary frame of a tomosynthesis image fromamong frames of reconstructed tomosynthesis images, it is necessary tocheck all the reconstructed tomosynthesis images on a frame-by-framebasis. According to one of the embodiments described above, atomosynthesis image not including information on the region of interestamong the reconstructed tomosynthesis images is not saved, enabling onlya necessary frame image to be displayed. This can improve diagnosticaccuracy and provide efficient use of the storage capacity. In addition,when tomosynthesis images are reconstructed, a tomosynthesis image framenot including information on the region of interest is automaticallyidentified and controlled, thereby reducing the load imposed on theoperator. Furthermore, an unnecessary frame not including the region ofinterest is selected from among reconstructed tomosynthesis image frameswithout requiring any operation performed by the operator, enablingefficient use of the storage capacity and enabling a reduction in theload imposed on the operator.

The advantages of the processes according to the embodiment describedabove will be described. In a case where a plurality of reconstructionprocesses are performed from the same projected image, storage of allthe reconstructed tomosynthesis images requires a large storage region.Alternatively, in the case of the same reconstruction parameters orimage processing parameters as those of an already reconstructedtomosynthesis image, the same image may occupy a plurality of displayareas when saved and displayed in parallel. This may affect the accuracyof image-based diagnosis or the efficiency of medical interpretation. Inaddition, recording of images in the order in which the images werereconstructed may hinder comparison because tomosynthesis imagesreconstructed under the same conditions may not be displayed in adjacentlocations depending on the order of reconstruction.

In the embodiment described above, the registration of tomosynthesisimages having different reconstruction parameters or image processingparameters among the reconstructed tomosynthesis images can improve theaccuracy of image-based diagnosis and provide efficient use of thestorage capacity. In addition, in the registration of tomosynthesisimages, tomosynthesis images having the same reconstruction parametersare added in a consecutive order, thereby facilitating comparison anddisplay. Furthermore, only tomosynthesis images having differentreconstruction parameters or image processing parameters are displayedwith similar images adjacent, thereby facilitating image-baseddiagnosis. Moreover, storage of only one set of tomosynthesis imageshaving the same reconstruction parameters or image processing parameterscan provide efficient use of the storage capacity.

<Reject Process>

Next, a process flow from when the start of reject and reconstructionprocesses in step S610 in FIG. 6 until a reject setting is performed isillustrated using FIG. 25.

In step S2501, a reject or re-imaging button is pressed. When a rejectinstruction is given, the operation unit 108 transmits a rejectnotification to the input/output control unit 407. When a re-imaginginstruction is given, the operation unit 108 transmits a re-imagingnotification to the input/output control unit 407. The rejectnotification and the re-imaging notification include selected imageinformation. Upon receipt of the reject notification, the input/outputcontrol unit 407 transmits the reject notification to the examinationcontrol unit 406. When a re-imaging instruction is given, theinput/output control unit 407 transmits a re-imaging notification to theexamination control unit 406.

In step S2502, upon receipt of the reject notification or the re-imagingnotification, the examination control unit 406 acquires selected imageinformation from the imaging technique information included in theexamination-scheduled-to-be-conducted information, and determineswhether or not a reject reason has been input.

If no reject reason has been input, in step S2503, the examinationcontrol unit 406 sets a reject reason in accordance with the operationinput from the operation unit 108. The examination control unit 406transmits a reject reason input screen transition notification to theinput/output control unit 407. Upon receipt of the reject reason inputscreen transition notification, the input/output control unit 407transmits the reject reason input screen transition notification to thedisplay unit 109. Upon receipt of the reject reason input screentransition notification, the display unit 109 displays a reject reasoninput screen. Thereafter, upon receipt of a reject reason confirmationinstruction in response to, for example, a confirmation button 2605being pressed, the operation unit 108 transmits a reject reason inputnotification to the input/output control unit 407. The reject reasoninput notification includes image information intended to be a rejectand a confirmed reject reason. Upon receipt of the reject reason inputnotification, the input/output control unit 407 transmits the rejectreason input notification to the examination control unit 406. At thesame time, the input/output control unit 407 transmits a reject reasoninput completion notification to the display unit 109. Upon receipt ofthe reject reason input completion notification, the display unit 109closes the reject reason input screen. Information on the reject reasonis output to the condition setting unit 4051.

Upon receipt of a reject reason cancellation instruction, the operationunit 108 transmits a reject reason cancellation notification to theinput/output control unit 407. Upon receipt of the reject reasoncancellation notification, the input/output control unit 407 transmitsthe reject reason cancellation notification to the examination controlunit 406. At the same time, the input/output control unit 407 transmitsa reject reason input completion notification to the display unit 109.Upon receipt of the reject reason input completion notification, thedisplay unit 109 closes the reject reason input screen. If no rejectreason is input, the condition setting unit 4051 may perform control soas not to perform a reject setting. This enables the management of areject with an explicit statement of grounds therefor. The reject reasonmay not necessarily be input, and the condition setting unit 4051 may beable to set a reject for data without requiring a reason for the reject.

In step S2504, the examination control unit 406 checks the imaging typeof the image intended to be a reject. The term imaging type, as usedherein, refers to either data of a projected image group or data of atomosynthesis image. Data intended to be a reject is determined by usingthe captured image thumbnail 1011 selected on the imaging screen 1001through an operation input when either the re-imaging button 1028 or thereject button 1029 is pressed.

If the data intended to be a reject indicates an image other than aprojected image, for example, a tomosynthesis image, in step S2504, thenin step S2511, the condition setting unit 4051 sets the reject settingin the image information on the target image to ON. For example, uponreceipt of the reject reason input notification, the condition settingunit 4051 acquires image information intended to be the reject from theimaging technique information included in theexamination-scheduled-to-be-conducted information, and saves the data inthe examination information storage unit 403 in association with a flagindicating a reject and information on the reject reason. The flag takesthe value 1 when indicating a reject, or the value 0 when indicating nota reject. Accordingly, the data is set as a reject.

Thus, in step S2514, the reject process is completed, and then theprocess ends.

If the imaging type indicates a projected image in step S2504, then instep S2505, the examination control unit 406 checks whether theinstructed process indicates a reject instruction (first instruction) ora re-imaging instruction (second instruction).

If a reject instruction is given in step S2505, then in step S2511, theexamination control unit 406 sets the reject setting in the imageinformation on the target image to ON.

Thus, in step S2514, the reject process is completed, and then theprocess ends.

If a re-imaging instruction is given in step S2505, the examinationcontrol unit 406 acquires all the pieces of image information includedin imaging technique information including the target projected imagefrom the held examination-scheduled-to-be-conducted information.

Then, in step S2506, the examination control unit 406 acquires a pieceof image information from the acquired pieces of image information.

Then, in step S2507, the examination control unit 406 checks whether ornot the reject reason in the acquired image information has been input.If the reject reason has not been input, the process proceeds to stepS2508 and the examination control unit 406 inputs the reject reason forthe target projected image to the reject reason in the acquired imageinformation. The details of this process are similar to those of stepS2503 described above.

Then, in step S2509, the examination control unit 406 checks the rejectsetting in the acquired image information.

If the reject setting is OFF, in step S2510, the condition setting unit4051 sets the reject setting in the acquired image information to ON.

In step S2511, the examination control unit 406 checks whether thereject setting is ON for all the pieces of image information. If thereis any image information in which the reject setting is OFF, the processreturns to step S2506 and the processes up to step S2512 are repeatedlyperformed.

If the reject setting has been made for all the pieces of imageinformation, in step S2513, the condition setting unit 4051 newlygenerates imaging information corresponding to the projected image, andsets the imaging information in the examination information as newimaging information. The display control unit 4070 causes the displayunit to display the new imaging information. Thus, the re-imagingprocess is completed, and then the process ends.

Through the process steps described above, if a re-imaging instructionis given for a projected image on which a tomosynthesis image is based,projected image and tomosynthesis images obtained based on the projectedimages are synchronously subjected to reject setting and reject reasoninput. This can reduce a time-consuming operation of performing a rejectprocess on the images one by one. In addition, if a reject reason hasalready been input through the execution of another reject process, ahigher priority is placed on the previously input reject reason, therebyaddressing a problem that a necessary reject reason may be overwrittendue to the re-imaging process. On the other hand, a reject process isperformed only on a selected image, which can support a use case inwhich a plurality of tomosynthesis images are generated and images otherthan necessary images are handled as rejects. In FIG. 25, if aninstruction for performing a reject process on a projected image isgiven, only a projected image is subjected to a reject process. However,if an instruction for performing a reject process on a projected imageis given in a way similar to that for a re-imaging process, the demandin which other images are also handled as rejects accordingly couldpresumably be expected. Such a demand can be easily met by, in thepresent invention, omitting the process in step S2505 for judgingwhether or not an instruction for performing a re-imaging process hasbeen given.

In a process according to another embodiment, even if the reject button1029 is pressed instead of the re-imaging button 1028, the followingprocess is executed. That is, in response to data of a projected imagegroup being set as a reject, the condition setting unit 4051 sets, as areject, the data of a tomosynthesis image generated based on theprojected image group. Accordingly, if it is determined that a projectedimage is inappropriate as a diagnostic image, regardless of whether ornot a re-imaging setting is performed, a tomosynthesis imagecorresponding to the inappropriate projected image group is determinedto be inappropriate, and is set as a reject. This process can reduce theproblem that an inappropriate tomosynthesis image is output to outsideand is used for diagnosis.

In contrast, even if the data of the tomosynthesis image is set as areject while the data of the projected image group is not set as areject, the condition setting unit 4051 does not set the data of theprojected image group as a reject. Tomosynthesis images for whichdiagnostic use is determined to be inappropriate in accordance with thereconstruction conditions and other process conditions can beindividually set as rejects, which can mitigate the problem in that aninappropriate tomosynthesis image is used for diagnosis.

Here, an example of a reject reason input screen 2601 displayed in stepS2503 in FIG. 25 is illustrated using FIG. 26. The reject input screen2601 is displayed in a pop-up window on the imaging screen 1001 in anarea that does not overlap the image display portion 1002. The rejectinput screen 2601 is a screen displayed when the re-imaging button 1028or the reject button 1029 is pressed through an operation input whilethere is a captured image thumbnail 1011 that is in a selected state onthe imaging screen 1001 illustrated in FIG. 10 or FIG. 24. Each of thecaptured image thumbnails 1011 is clicked through an operation input tothe operation unit 108, thereby entering into the selected state. In thecontrol of bringing one of the captured image thumbnails 1011 into theselected state, for example, the input of a click on the captured imagethumbnail 1011 is detected by the input detection unit 4071, therebyallowing the examination control unit 406 to set the captured imagethumbnail 1011 to the selected state. In this regard, the examinationcontrol unit 406 functions as a selection unit that selects at least oneof the data of the projected image group and the data of thetomosynthesis image.

The reject button 1029 is a button (first button) for allowing thecondition setting unit 4051 to execute a reject setting. The re-imagingbutton 1028 is a button (second button) for executing a re-imagingsetting to set imaging information for executing re-imaging for the dataselected by the condition setting unit 4051. In accordance with there-imaging button being pressed, the condition setting unit 4051executes a reject setting to set at least one of the data of thetomosynthesis image or the data of the projected image group as areject. In addition to this, the condition setting unit 4051 executes are-imaging setting to set imaging information for executing re-imagingfor the data.

If a reject setting is made, the display control unit 4070 causes thecaptured image thumbnails 1011 indicating the data of the tomosynthesisimage and the data of the projected image group to be displayed. Inaddition to this, the display control unit 4070 causes a mark indicatingwhether or not the corresponding image has been set as a reject by thecondition setting unit 4051 to be displayed superimposed on each of thecaptured image thumbnails 1011. This allows each of the captured imagethumbnails 1011 to intelligibly show whether or not the correspondingdata is a reject. The display in FIG. 26 is not to be taken in alimiting sense, and the display control unit 4070 causes a mark (x) foran image when set as a reject or a circle (◯) for an image not set as areject to be displayed superimposed on each of the captured imagethumbnails 1011. In the manner described above, a mark indicatingwhether or not the corresponding data has been set as a reject isdisplayed superimposed on each of the captured image thumbnails 1011,allowing intelligible showing of whether a reject has occurred or not.

In an imaging control device 107 according to one embodiment, in a casewhere, as in the imaging screen 1001 in FIG. 10, a captured imagethumbnail 1011 corresponding to a projected image group is in theselected state, the display control unit 4070 causes both the rejectbutton 1029 and the re-imaging button 1028 to be displayed. This enablesthe operator to select whether the projected image group is simplyregarded as a reject or is regarded as a reject and then subjected tore-imaging, enabling output control and re-imaging to be easily executedin accordance with the situation.

In contrast, as illustrated in FIG. 28, in a case where a captured imagethumbnail 1011 corresponding to a tomosynthesis image is in the selectedstate, the display control unit 4070 makes the re-imaging button 1028invisible. The reason for this is as follows. Since a tomosynthesisimage obtained by reconstruction does not exactly have a concept ofre-imaging, this point is clearly stated. Doing so enables the displaycontrol unit 4070 and the examination control unit 406 that controls thedisplay control unit 4070 to execute control in which the execution ofre-imaging setting is not permitted for a tomosynthesis image while theexecution of re-imaging setting is permitted only for a projected imagegroup. This is not to be taken in a limiting sense, and the examinationcontrol unit 406 may also cause the re-imaging button 1028 to bedisplayed when either of a tomosynthesis image and a projected imagegroup is selected. Instead, the examination control unit 406 can performcontrol so that even if the re-imaging button 1028 is pressed, thecorresponding process is not executed. Additionally, a similar purposecan be achieved by the display control unit 4070 causing the re-imagingbutton 1028 to be displayed as unselectable in a case where the data ofthe tomosynthesis image is in the selected state.

In another embodiment, in response to the re-imaging button 1028 beingpressed while a tomosynthesis image is selected, the condition settingunit 4051 is configured to execute re-imaging for the tomosynthesisimage. In this case, the condition setting unit 4051 generates newimaging information, and associates the new imaging information with thesame examination information as the original imaging information. Thenew imaging information is displayed as, for example, an imagingtechnique display portion 1009 b in FIG. 27, in parallel with anoriginal imaging technique display portion 1009 a by the display controlunit 4070. Here, for the new imaging information, the condition settingunit 4051 makes the process conditions (reconstruction conditions andimage processing conditions) for the tomosynthesis image identical tothe process conditions for a tomosynthesis image that is in the selectedstate when the re-imaging is set. The new imaging information is alsoset to be identical to the imaging information (imaging techniqueinformation displayed in the imaging technique display portion 1009 a)corresponding to the tomosynthesis image that is in the selected statedescribed above. Doing so enables imaging to be efficiently re-executedin a case where, for example, the imaging has failed due to a motion ofthe object. The condition setting unit 4051 is also capable of changingthe driving conditions included in the new imaging information (imagingtechnique), the irradiation conditions, and the image processingconditions for recursive processing or other processing to be performedon a projected image in accordance with the operation input of theoperation unit 108. This can provide re-imaging to be executed in orderto address an insufficient number of projected images or inappropriateirradiation conditions.

By doing so, in response to the irradiation switch 103 being pressedwhile new imaging information is selected, the imaging control unit 405causes a projected image group corresponding to the new imaginginformation to be captured. In accordance with the completion of thecapture of the projected image group, the imaging control unit 405causes the image processing unit 110 to start a tomosynthesis imagegeneration process, that is, a reconstruction process and toneconversion processing. In this case, the reconstruction processing unit1611 executes a reconstruction process and tone conversion processing inaccordance with the process conditions described above. Thus, theimaging control unit 405 performs control so that an analysis process isnot executed by the tone conversion parameter acquisition unit 1612. Bydoing so, if the process conditions for tomosynthesis images areappropriate, re-imaging based on one of the tomosynthesis images can beexecuted for more appropriate imaging of projected images, which isefficient.

The reject button 1029 and the re-imaging button 1028 described aboveare displayed on the imaging screen 1001 together with the capturedimage thumbnails 1011 that are indications indicating the data of thetomosynthesis image and the data of the projected image group. Thisenables the operator to perform a reject setting and input a rejectreason while viewing a preview of an image for the reject setting andthe input of the reject reason, achieving the advantage of making iteasy to study the reject reason.

The reject reason input screen 2601 is constituted by a reject reasoninput portion 2602, a reject reason selection portion 2603, acancellation instruction portion 2604, and a confirmation instructionportion 2605. The reject reason input portion 2602 is a control forinputting a reject reason. The reject reason selection portion 2603 is acontrol for displaying reject reasons registered in the control unit 111in list form. When a reject reason is selected from the list, theselected reject reason is input to the reject reason input portion 2602.As reject reasons, reject reasons confirmed through system settings inadvance and confirmed through the reject reason input screen 2601 in thepast are registered. The cancellation instruction portion 2604 is abutton for providing an instruction to discard an input reject reason.In accordance with a cancellation instruction, the content of the inputreject reason is discarded and the reject reason input screen 2601 isclosed. The screen confirmation instruction portion 2605 is a button forproviding an instruction to confirm a reject reason. In accordance witha confirmation instruction, the content of an input reject reason isconfirmed and the reject reason input screen 2601 is closed. The rejectreason input screen 2601 having the configuration described above isdisplayed.

When the content of an input reject reason is confirmed, the conditionsetting unit 4051 sets, as a reject, the data corresponding to thecaptured image thumbnail 1011 that is in the selected state.

Here, an example of the imaging screen 1001 displayed when there-imaging process for a tomosynthesis imaging technique is completed instep S2513 in FIG. 25 is illustrated using FIG. 27. When the re-imagingprocess for the tomosynthesis imaging technique is completed, the rejectmarks 2701 are respectively displayed on all the captured imagethumbnails 1011 included in the imaging technique display portion 1009 afor the tomosynthesis imaging technique for which the re-imaging processhas been executed. The form of the reject marks 2701 is not limited solong as it is possible to recognize a reject state. In addition, thesame imaging technique display portion 1009 b as the tomosynthesisimaging technique for which the re-imaging process has been executed isadded immediately below the imaging technique display portion 1009 a.Thereafter, the imaging technique display 1009 b is selected as intendedfor the next imaging, and the intended-for-imaging thumbnail 1012 isdisplayed in the imaging technique display 1009 b. Further, in a casewhere a captured image thumbnail 1011 of a projected image included inthe tomosynthesis imaging technique for which re-imaging has beenexecuted is selected as a preview, the re-imaging button 1029 becomesinvisible and the display area is cut out from the display. Further, ina case where a captured image thumbnail 1011 for which the rejectprocess has been executed is displayed as a preview, the reject button1029 becomes invisible and a reject clearance instruction portion 2702is displayed in the same display area as that of the reject button 1029.The reject clearance instruction portion 2702 is a button for providingan instruction to clear the setting of the reject for the imagesubjected to the reject setting, which is currently being selected as apreview. When the reject process is canceled, the reject settingincluded in the image information is switched to OFF. The imaging screen1001 having the configuration described above is displayed.

Here, an example of the imaging screen 1001 displayed when the rejectprocess is completed in step S2514 in FIG. 25 is illustrated using FIG.28. When the reject process is completed, the reject mark 2701 isdisplayed only on the captured image thumbnail 1011 of the image forwhich the reject process has been executed. The imaging screen 1001having the configuration described above is displayed.

Additionally, in addition to the embodiments described above, forexample, if one or a plurality of tomosynthesis images are present infirst imaging information displayed in the imaging technique displayportion 1009 a, the display control unit 4070 executes the followingprocess. That is, in response to all the tomosynthesis images being setas rejects, the display control unit 4070 is configured to display atleast either a warning or an indication asking whether or not to executethe reconstruction of a new tomosynthesis image. Since tomosynthesisimaging is originally performed in order to obtain a tomosynthesisimage, if all the generated tomosynthesis images are regarded asrejects, it is considered that the intended purpose of the imaging isnot achieved. Accordingly, as described above, the display of a warningor a GUI for prompting re-imaging can help perform tomosynthesis imagingas appropriate. In the example described above, the setting of all thetomosynthesis images as rejects is used as a trigger, but is not limitedthereto. For example, in a case where there are three tomosynthesisimages, a specified number of tomosynthesis images or more, for example,two or more tomosynthesis images, may be set as rejects. Alternatively,each time one tomosynthesis image is set as a reject, the displaydescribed above may be provided.

In addition, taking it into account that a projected image group ortomosynthesis image group includes a plurality of images, the conditionsetting unit 4051 is capable of setting some of the projected imagesincluded in the projected image group as rejects (executing a firstsetting). Alternatively, the condition setting unit 4051 is capable ofsetting some of a plurality of slice images included in a tomosynthesisimage as rejects (executing a second setting). For example, if only someprojected images have a problem due to a motion of the body or any othereffect, such projected images are set as rejects, thereby contributingto the generation of a more appropriate tomosynthesis image. Inaddition, if some slice images of a tomosynthesis image areinappropriate, such projected images are set as rejects, which cansupport more accurate diagnosis.

In response to the first setting described above being performed, thereconstruction processing unit 1611 executes a reconstruction processbased on projected images except for some projected images for which thefirst setting has been made. By doing so, if an inappropriate projectedimage is found, a tomosynthesis image on which the effect of theinappropriate projected image is eliminated is automatically generated,which can provide efficient support for imaging. Similarly to theexample described above, if there is a tomosynthesis image reconstructedby using the projected images set as rejects, the condition setting unit4051 sets the image as a reject, thereby preventing an inappropriatetomosynthesis image from being used for diagnosis. In addition, theimage processing unit 110 prohibits the generation of an oblique imagein a direction with respect to the direction of irradiation for theprojected images, or the display control unit 4070 performs control toprohibit the display of the oblique image. For example, projected imageswith an irradiation direction of −25 degrees to −20 degrees are set asrejects. In this case, a range smaller than −20 degrees is eliminatedfrom a display range of oblique images, yielding a range of ±20 degrees,or only a range of −25 degrees to −20 degrees is eliminated.

In another exemplary embodiment, instead of immediately generating atomosynthesis image or performing a reject setting in accordance withsome projected images being set as rejects, the reconstructionprocessing unit 1611 defers the judgment to the operator. In accordancewith the first setting being performed, the display control unit 4070enables the display of a GUI for providing an instruction as to whetheror not to execute a reconstruction process based on a projected imagegroup in which some projected images have been set as rejects, or amessage which recommends the execution of the reconstruction process.Alternatively, a message indicating that a tomosynthesis image based onthe projected image group in which some projected images have been setas rejects is present can be displayed. Any combination of them can alsobe displayed. Doing so can prevent an unnecessary reconstruction processor reject process from being performed, and can improve imagingefficiency.

The advantages of processes according to one of the embodimentsdescribed above will be described. In a case where a plurality oftomosynthesis images are reconstructed from the same projected image, ifthe original projected image is subjected to a reject process, thetomosynthesis images can probably be regarded as rejects in most cases.This probability is higher when a re-imaging instruction forre-performing imaging is given. Thus, if a projected image is subjectedto a reject process later, it may be time and labor consuming to furtherexecute a reject process on other tomosynthesis images one by one.Further, if it is required that a reject reason be input when a rejectprocess is executed, it is also necessary to input a reject reason foreach image. Accordingly, a reject process is easily executed for atomosynthesis imaging technique and the ON/OFF setting of the imageoutput is enabled, thereby reducing the load imposed on the operator.Meanwhile, as described above, a reject process is associated withON/OFF of the image external output target. This enables a rejectprocess to be individually performed on an image simply judged not tohave to be output to outside in addition to an image for which imagingor reconstruction has failed, in which case control can be performed sothat, in response to a reject process being performed on one image,other images are also subjected to a reject process accordingly.

<Other Embodiments>

In the example described above, an embodiment of an X-ray imaging systemhas been illustrated, but is not limited thereto. Devices capable oftomosynthesis imaging or tomographic imaging, such as MRI, PET, andSPECT, or an image management device or an image processing device thathandles images from such devices may implement the present invention.

As an alternative, any combination of the embodiments described above isalso included in embodiments of the present invention. Alternatively, ina case where the processes described above are executed in cooperationof a program with hardware, the program or a storage medium storing thesame is also included in an embodiment of the present invention. Anembodiment of a program is implemented by a program for the processesdescribed above, and by storing the program in a storage unit, loadingthe program onto a RAM by using a CPU of an electronic calculator or acomputer, and executing instructions included in the program by usingthe CPU.

In respect of the additional display control of an icon described withreference to FIGS. 23 and 24, in another embodiment, even when theconditions for creating a new icon described above are satisfied, it ispossible to switch between a setting for immediately creating an iconand a setting for not immediately creating an icon but creating ordisplaying an icon after, for example, the authentication of a user.Information indicating such settings is stored in a memory of theimaging control device 107 by the control unit 111. Such settings can bechanged through the operation input of the operation unit 108.

In a case where the setting for not immediately creating an icon ismade, before step S2310 and S2311 in FIG. 23, the display control unit4070 causes the display of a window for selecting, through an operationinput, whether or not to cause the display unit to display a new iconrepresenting a tomographic image based on changed or set conditions.This window shows a first icon or button used to accept an operationinput for display, and a second icon or button used to accept anoperation input for not display, together with a message asking the userabout selection. If an operation input for the first icon is made, thedisplay control unit 4070 executes an icon addition display processcorresponding to step S2310 or S2311. If an operation input for thesecond icon is made, the processes of steps S2310 and S2311 to S2313 arenot performed. Doing so can provide user-desired control for icondisplay.

In another embodiment, the case of displaying an icon, the case ofdisplaying a newly added icon instead of one icon selected by the user,and the case of adding no icons may be switched over. Such switching isenabled by a setting for displaying a newly added icon instead of oneicon selected by the user, and, while this setting is made, the displaycontrol unit 4070 causes a new icon to be displayed instead of aselected single icon in accordance with the operation input to theoperation unit 108 by the user. In another example, furthermore, thewindow described above shows a third icon or button used to accept anoperation input for the display of a newly added icon instead of oneicon selected by the user. In accordance with the operation input forthe third icon and an operation input for selecting the one iconcorresponding to a thumbnail, the display control unit 4070 causes a newicon to be displayed instead of the selected single icon. In thisembodiment, in a case where a set of tomographic images before thechange is not necessary, such as in the case where the reconstructionconditions or image processing conditions have been finely corrected, nounnecessary thumbnail is displayed, which can facilitate the managementof reconstructed tomographic images. However, even if conditions arefinely corrected, a tomographic image before the change and atomographic image after the change are used for diagnoses for differentpurposes, which is useful for the transfer of both tomographic images tothe PACS 115.

In another embodiment, even if it is determined in step S2306 that thereconstruction parameters and the image processing parameters areidentical, as described above, a GUI for prompting the user to selectwhether or not to add an icon is displayed. This function is useful forthe separate management of, for example, a tomographic image to betransferred to the PACS 115, a tomographic image to be transferred tothe printer 117, and a tomographic image to be transferred to aworkstation (not illustrated). For example, one conceivable case is thatdifferent ranges are cropped from tomographic images obtained under thesame conditions, and are output.

In another embodiment, in a case where the same reconstructionconditions as those for an already reconstructed tomographic image havebeen set, a confirmation button 1121 is prevented from being pressed.This process is executed by performing the processes of steps S2302 toS2309 in accordance with the reconstruction conditions displayed in FIG.22 before the confirmation button 1121 is pressed. This can reduce thereconstruction of an unnecessary tomographic image or the display of athumbnail.

Another embodiment will be described with reference to FIG. 29. Thecontrol unit 111 controls an angle interval ΔΦ of obliquecross-sectional images ◯ which are adjacent for the display of obliquecross-sectional images on the basis of an interval ΔΘ of projectionangles at which projected images P are captured (in the imaging systemin FIG. 2, angles from −XX deg. to +XX deg.). Consideration is given tothe case where, while the projection angle is changed over a range fromthe projection angle −XX deg. to the projection angle +XX deg., X-rayirradiation is performed N times to obtain N projected images P. Thedifference between the projection angle Θn for the n-th (n<N−1) X-rayirradiation and the projection angle Θn+1 for the (n+1)-th X-rayirradiation is defined as ΔΘ. ΔΘ may be constant regardless of n, or maybe different for each n. Even if ΔΘ is controlled to be constantregardless of n, resulting projected images may not exactly match due toany error caused by a motor and the like. For example, variations witherrors less than or equal to 5% of ΔΘ may be handled as identical.

The value of ΔΘ may be calculated based on Θn. The value of Θn isacquired from the X-ray control unit 104 or the movement mechanismcontrol unit 1063 as geometric information for each projected image.Alternatively, the value of ΔΘ may be directly acquired from the X-raycontrol unit 104 or the movement mechanism control unit 1063.

In one embodiment, if ΔΘ is constant, the angle interval of obliquecross-sectional images is given by ΔΦ=ΔΘ, and serves as an angleinterval over which oblique cross sections are sequentially displayed.For example, the mouse cursor is placed over the 3D slider in FIG. 12 orthe 3D slider is selected to be in focus. In this case, it is assumedthat an oblique cross-sectional image On oriented at an angle of Φn withrespect to the coronal plane (the detection surface of the X-raydetector) is being displayed. In this state, the up-arrow key on thekeyboard is pressed once, thereby displaying an oblique cross-sectionalimage On+1 with an angle Φn+1 with respect to the coronal plane, whichis given by Φn+1−Φn=ΔΦ=ΔΘ. In this case, desirably, Φn=Θn. By doing so,the oblique image ◯ is an image of a cross section in an irradiationdirection Θ which is the normal direction, resulting in an increase inthe quality of the oblique image. Even if Φn=Θn is not satisfied,reducing Δ of Φn=Θn±Δ to 25 percent or less of ΔΘ can reduce thedifference between Φn and Θn, achieving the advantage of improving imagequality compared to the case of exceeding 25%. Even if ΔΘ is notconstant, making ΔΘn and ΔΦn identical or reducing the differencebetween Φn and Θn can improve image quality.

In another embodiment, the control unit 111 causes the display of anoblique image of a cross section not passing through the isocenter.While an image of a cross section not passing through the isocenterprovides improved quality for a tomosynthesis image, in some cases, across-sectional image passing through the isocenter may not necessarilybe an image suitable for observation since the operator may wish toobserve a fracture at a specific position in a specific direction, forexample. For example, if a setting for displaying an oblique image of across section not passing through the isocenter is made, the displaycontrol unit 111 causes such an oblique image to be displayed, whereasif a setting for displaying an oblique image of a cross section notpassing through the isocenter is not made, the display control unit 111does not cause such an oblique image to be displayed. The settinginformation is stored in the memory of the imaging control device 107,and can be changed by a user in accordance with an operation through theoperation unit 108. For an oblique image of a cross section not passingthrough the isocenter, which is displayed when a setting for displayingan oblique image of a cross section not passing through the isocenter ismade, as described in the embodiment described above, the angle Φ withrespect to the coronal plane is set to be equal to any of the projectionangles θ of the projected images P, whereby the image quality can beguaranteed to some extent.

In another embodiment, consideration is given to the case where some ofa plurality of projected images are designated as rejects. In this case,the control unit 111 controls image processing on the basis of positioninformation corresponding to projected images set as rejects. Forexample, consideration is given to the case where, while the projectionangle is changed over a range from the projection angle −XX deg. to theprojection angle +XX deg., X-ray irradiation is performed N times toobtain N projected images Pn (n≤N). For example, a projected image at oraround the lower limit or upper limit of the projection angle, such asany of P1 to P3 or any of PN-2 to PN, is designated as a reject. In thiscase, the image processing unit 110 performs reconstruction by using(N-6) projected images in total, namely, P4 to PN-3. In this case,similar consideration to the case where the range of projection anglesis initially narrowed to a small range may apply. That is, thistomosynthesis is similar to that in which the X-ray generation unitperforms imaging while being moved over a range of θ4 to θN-3, where θ4denotes the projection angle for P4 and θN-3 denotes the projectionangle for PN-3.

In the manner described above, even if some of a plurality of projectedimages are designated as rejects, a reconstructed image is not regardedas a reject and reconstruction is re-performed by using projected imagesthat are not rejects, which can provide effective use of data obtainedthrough X-ray irradiation.

Needless to say, as mentioned in the exemplary embodiment describedabove, the display of oblique cross-sectional images is limited on thebasis of the projection angles. Accordingly, if the display of anintended oblique cross-sectional image is not available, re-imaging isperformed. Here, for example, a certain oblique cross-sectional image isdesignated as an image for PACS transfer. In this case, if someprojected images of a projected image group that is data on which theoblique cross-sectional image is based are designated as rejects and thedisplay of the oblique cross-sectional image is limited,three-dimensional volume data (tomographic images) including the obliquecross-sectional image may be set as a reject in accordance with theprojected images of the projected image group being designated asrejects. Alternatively, in accordance with the projected images of theprojected image group being designated as rejects, the display controlunit 4070 may cause the display of a dialog asking the user whether ornot the three-dimensional volume data (tomographic images) is regardedas a reject, so that the designation of a reject is deferred to theoperation input of the user. If there is an operation input indicatingthat the three-dimensional volume data is designated as a reject, thecontrol unit 110 designates the three-dimensional volume data as areject and cancels the designation of the oblique cross-sectional imageas that for PACS transfer. Alternatively, the cancellation of PACStransfer may be deferred to the operation input of the user. If there isno operation input indicating that the three-dimensional volume data isdesignated as a reject, the control unit 110 does not designate thethree-dimensional volume data as a reject nor does the control unit 110cancel the PACS transfer designation. The oblique cross-sectional imageis output to the PACS 115 through the communication circuit 112.

In the manner described above, if some of projected images aredesignated as rejects, whether or not a reconstructed tomographic imageis also regarded as a reject accordingly is deferred to the operationinput of the user, thereby executing the user-desired processing andreducing the labor for operation input. In addition, since thedesignation as PACS transfer can also be canceled along with rejectdesignation, the labor for the processing can be reduced.

Consideration is now given to the case where a projected image PN′ hasbeen designated as a reject, where N′ is an integer satisfying N′=N/2.In this case, a projected image obtained by X-rays emitted from theX-ray generation unit 102 at a position almost immediately above theisocenter or at the position with a projection angle of approximately 0°is not able to be used for reconstruction. In this case, the imageprocessing unit 110 does not re-perform reconstruction of a tomographicimage since image quality is not sufficiently guaranteed.

In another embodiment, there is no significant problem if only oneprojected image at a projection angle of 0° is not able to be used forreconstruction, and accordingly the image processing unit 110 performsreconstruction by using projected images except for the projected imagedesignated as rejects, which can provide effective use of data obtainedby X-ray imaging. In this case, the image processing unit 110 isconfigured to perform reconstruction if, for example, the number ofavailable projected images does not exceed M that is a threshold value,and not to perform reconstruction if M is exceeded.

In the manner described above, the control unit 111 controls whether ornot to perform reconstruction in accordance with position information onthe projected images designated as rejects, the projection angle, or thenumber of projected images, or a combination of them. This prevents thereconstruction of a tomographic image whose image quality is notguaranteed while providing effective use of data obtained by X-rayirradiation, leading to less likelihood of false diagnosis.

In the example described above, a description has been given of the casewhere projected images are designated as “rejects”. In the exemplaryembodiment described above, by way of example, the term “reject” refersto, but is not limited to, failed imaging, which is decided on throughthe operation input of the user. For example, similar processing mayalso be performed on, an image determined as a defective image by theimage processing unit 110.

As an alternative, in step S608 described above, the display controlunit 4070 causes the display unit 109 to sequentially display projectedimages upon sequentially receiving the projected images during thecapture of projected images. This enables the user to make sure thatsuccessively captured projected images have no problem during imaging.In accordance with the completion of the capture of projected images instep S608, the image processing unit 110 executes a reconstructionprocess. In accordance with the completion of the reconstruction, thedisplay control unit 4070 displays a tomosynthesis image obtainedthrough the reconstruction on the display unit 109. The series ofprocesses described above is controlled by the imaging control unit 405.Accordingly, a reconstruction process is performed in accordance withthe completion of the capture of projected images, enabling a quickcheck of tomosynthesis images.

In the manner described above, the display of projected images duringthe capture of projected images helps the user easily check a problemregarding the capture of projected images. Quick display of atomosynthesis image after the completion of the capture of projectedimages helps the user easily make sure that there is no problem inreconstruction. This facilitates checking whether or not re-imaging isnecessary on the basis of both projected images and a reconstructedimage.

In the embodiment described above, for example, the functions of theimaging control device 107 may be distributed to a plurality of devicescapable of communicating with each other, thereby implementing thefunctions of the imaging control device 107 as a control system. Forexample, the functions of the image processing unit 110 may be providedfor an external server, by way of example. The external server may belocated in a control room or an imaging room where an X-ray imagingsystem for performing tomosynthesis imaging is installed, and may beconnected via a dedicated LAN. The external server may also be locatedin the hospital, and may perform communication over a LAN in thehospital. Alternatively, the external server may be located in a datacenter or the like outside the hospital either locally or overseas, anddata may be exchanged via secure communication methods such as VPN.

The present invention is not limited to the embodiments described above,and a variety of changes and modifications can be made without departingfrom the spirit and scope of the present invention. Therefore, toapprise the public of the scope of the present invention, the followingclaims are provided.

This application claims the benefit of Japanese Patent Application No.2013-127975 filed Jun. 18, 2013, which is hereby incorporated byreference herein in its entirety.

The invention claimed is:
 1. A control device for controllingtomosynthesis imaging for obtaining a tomosynthesis image from aprojected image group captured by irradiating an object with X-rays froma plurality of different angles by using an X-ray generation unit and anX-ray detection unit, the control device comprising: one or moreprocessors which, by executing instructions, cause the control device tofunction as: a setting unit that sets at least one of projected imagesof the projected image group as a reject, wherein the setting unit setsthe tomosynthesis image generated by reconstruction using the projectedimage group including the at least one of the projected images set asthe reject, as a reject; a communication circuit that transmits at leasteither of a tomosynthesis image and the projected image group to anexternal device; an output control unit for limiting transmission ofdata set as a reject to the external device; and a display control unitthat causes an indication indicating each of the tomosynthesis image andthe projected image group to be displayed and further causes a markindicating whether or not the corresponding at least one of theprojected images has been set as a reject by the setting unit to besuperimposed on the indication, wherein the display control unit causesan indication corresponding to the at least one of the projected imagesset as a reject by the setting unit to have superimposed thereon a markindicating that the at least one of the projected images has been set asa reject, wherein the display control unit causes first imaginginformation for capturing a projected image group to be displayed in afirst display area, and, in response to the projected image groupcorresponding to the first imaging information being captured, causes athumbnail image indicating the projected image group to be displayed inthe first display area, and in response to a tomosynthesis image basedon the projected image group being generated, the display control unitcauses a thumbnail image of the tomosynthesis image to be displayed inthe first display area.
 2. The control device according to claim 1,wherein the setting unit executes a reject setting to set at least oneof the tomosynthesis image or the projected image group as a reject, anda re-imaging setting to set imaging information for executing re-imagingfor the tomosynthesis image or the projected image group.
 3. The controldevice according to claim 2, wherein the one or more processors which,by executing the instructions, further cause the control device tofunction as a control unit that performs control so that execution ofthe re-imaging setting is permitted for the projected image group andexecution of the re-imaging setting is not permitted for thetomosynthesis image.
 4. The control device according to claim 1, whereinthe one or more processors which, by executing the instructions, furthercause the control device to function as: a selection unit that selects aprocess condition of a tomosynthesis image corresponding to the firstimaging information; and an image processing unit that processes, inresponse to the selection, a tomosynthesis image corresponding to secondimaging information different from the first imaging information inaccordance with the selected process condition.
 5. The control deviceaccording to claim 1, wherein the one or more processors which, byexecuting the instructions, further cause the control device to functionas a display control unit that causes a first button for setting thereject to be displayed together with an indication indicating each ofthe tomosynthesis image and the projected image group.
 6. The controldevice according to claim 5, wherein the display control unit causes afirst button for setting a reject, and a second button for setting areject and providing an instruction to perform re-imaging to bedisplayed together with an indication indicating each of thetomosynthesis image and the projected image group.
 7. The control deviceaccording to claim 6, wherein the one or more processors which, byexecuting the instructions, further cause the control device to functionas a selection unit that selects at least one of the projected imagegroup or the tomosynthesis image, wherein the display control unitenables pressing of the first and second buttons while the projectedimage group is being selected, and disables pressing of the secondbutton while the tomosynthesis image is being selected.
 8. The controldevice according to claim 6, wherein the display control unit makes thefirst and second buttons visible while the projected image group isbeing selected, and makes the second button invisible while thetomosynthesis image is being selected.
 9. The control device accordingto claim 6, wherein in response to the second button being pressed, thesetting unit executes a reject setting to set at least one of thetomosynthesis image or the projected image group as a reject, and are-imaging setting to set imaging information for executing re-imagingfor the tomosynthesis image or the projected image group.
 10. Thecontrol device according to claim 1, wherein the one or more processorswhich, by executing the instructions, further cause the control deviceto function as a display control unit that causes at least either awarning or an indication asking whether or not to execute reconstructionof a new tomosynthesis image to be displayed in response to a specifiednumber of tomosynthesis images or more being set as a reject for atleast one tomosynthesis image corresponding to the first imaginginformation.
 11. The control device according to claim 1, wherein thesetting unit executes either of a first setting for setting a certainprojected image included in the projected image group as a reject and asecond setting for setting a certain slice image included in thetomosynthesis image as a reject.
 12. The control device according toclaim 11, wherein the one or more processors which, by executing theinstructions, further cause the control device to function as areconstruction unit that executes, in accordance with the first settingbeen executed, a reconstruction process based on projected images exceptfor the certain projected image for which the first setting has beenmade.
 13. The control device according to claim 12, wherein the one ormore processors which, by executing the instructions, further cause thecontrol device to function as a display control unit that causes adisplay unit to display, in accordance with the first setting beingperformed, at least any one of a GUI for providing an instruction as towhether or not to execute a reconstruction process based on a projectedimage group in which the certain projected image has been set as areject, a message which recommends execution of the reconstructionprocess, and a message indicating that a tomosynthesis image based onthe projected image group in which the certain projected image has beenset as a reject is present.
 14. An X-ray imaging apparatus comprising:the control device according to claim 1; and the X-ray detector.
 15. AnX-ray imaging system comprising: the control device according to claim1; the X-ray detector; the X-ray generation unit; and the display unit.16. The control device according to claim 1, wherein the one or moreprocessors which, by executing the instructions, further cause thecontrol device to function as a limitation unit that, in accordance withthe number of projected images designated as rejects or a projectionangle corresponding to the projected images within the projected imagegroup, limits reconstruction based on a projected image not designatedas a reject within the projected image group.
 17. A control device forcontrolling tomosynthesis imaging for obtaining a tomosynthesis imagefrom a projected image group captured by irradiating an object withX-rays from a plurality of different angles by using an X-ray generationunit and an X-ray detection unit, the control device comprising: one ormore processors which, by executing instructions, causes the controldevice to function as: a selection unit that selects at least one of theprojected image group or the tomosynthesis image; an instruction unitthat executes at least any one of a first instruction for providing aninstruction to set the selected tomosynthesis image or the projectedimage group as a reject, and a second instruction for providing aninstruction to re-acquire the selected tomosynthesis image or theprojected image group; a setting unit that, in a case where the selectedtomosynthesis image or the projected image group indicates the projectedimage group, sets the projected image group as a reject in response tothe first instruction having been given, and sets the projected imagegroup and the tomosynthesis image based on the projected image group asrejects in response to the second instruction having been given; acommunication circuit that transmits at least either a tomosynthesisimage and the projected image group to an external device; an outputcontrol unit for limiting transmission of data set as a reject to theexternal device; and a display control unit that causes an indicationindicating each of the tomosynthesis image and the projected image groupto be displayed and further causes a mark indicating whether or not thecorresponding at least one of the projected images has been set as areject by the setting unit to be superimposed on the indication, whereinthe display control unit causes an indication corresponding to the atleast one of the projected images set as a reject by the setting unit tohave superimposed thereon a mark indicating that the at least one of theprojected images has been set as a reject, wherein the display controlunit causes first imaging information for capturing a projected imagegroup to be displayed in a first display area, and, in response to theprojected image group corresponding to the first imaging informationbeing captured, causes a thumbnail image indicating the projected imagegroup to be displayed in the first display area, and in response to atomosynthesis image based on the projected image group being generated,the display control unit causes a thumbnail image of the tomosynthesisimage to be displayed in the first display area.
 18. A control methodfor controlling tomosynthesis imaging for obtaining a tomosynthesisimage from a projected image group captured by irradiating an objectwith X-rays from a plurality of different angles by using an X-raygeneration unit and an X-ray detection unit, the control methodcomprising: a setting step of setting at least one of projected imagesof the projected image group as a reject, wherein the setting step setsthe tomosynthesis image generated by reconstruction using the projectedimage group including the at least one of the projected images set asthe reject, as a reject, a step of limiting transmission of data set asa reject to an external device, and a display control step of causing anindication indicating each of the tomosynthesis image and the projectedimage group to be displayed and further causing a mark indicatingwhether or not the corresponding at least one of the projected imageshas been set as a reject by the setting step to be superimposed on theindication, wherein the display control step causes an indicationcorresponding to the at least one of the projected images set as areject by the setting step to have superimposed thereon a markindicating that the at least one of the projected images has been set asa reject, wherein the display control step causes first imaginginformation for capturing a projected image group to be displayed in afirst display area, and, in response to the projected image groupcorresponding to the first imaging information being captured, causes athumbnail image indicating the projected image group to be displayed inthe first display area, and in response to a tomosynthesis image basedon the projected image group being generated, the display control stepcauses a thumbnail image of the tomosynthesis image to be displayed inthe first display area.
 19. A control method for controllingtomosynthesis imaging for obtaining a tomosynthesis image from aprojected image group captured by irradiating an object with X-rays froma plurality of different angles by using an X-ray generation unit and anX-ray detection unit, the control method comprising: a step of selectingat least one of the projected image group or the tomosynthesis image; astep of providing at least any one of a first instruction for providingan instruction to set the selected tomosynthesis image or the projectedimage group as a reject, and a second instruction for providing aninstruction to re-acquire the selected tomosynthesis image or theprojected image group; a step of, in a case where the selectedtomosynthesis image or the projected image group indicates the projectedimage group, setting the projected image group as a reject in responseto the first instruction having been given, and setting the projectedimage group and the tomosynthesis image based on the projected imagegroup as rejects in response to the second instruction having beengiven; a step of limiting transmission of data set as a reject to anexternal device; and a step of display control that causes an indicationindicating each of the tomosynthesis image and the projected image groupto be displayed and further causes a mark indicating whether or not thecorresponding at least one of the projected images has been set as areject by the step of setting to be superimposed on the indication,wherein the step of display control causes an indication correspondingto the at least one of the projected images set as a reject by the stepof setting to have superimposed thereon a mark indicating that the atleast one of the projected images has been set as a reject, wherein thestep of display control causes first imaging information for capturing aprojected image group to be displayed in a first display area, and, inresponse to the projected image group corresponding to the first imaginginformation being captured, causes a thumbnail image indicating theprojected image group to be displayed in the first display area, and inresponse to a tomosynthesis image based on the projected image groupbeing generated, the step of display control causes a thumbnail image ofthe tomosynthesis image to be displayed in the first display area.
 20. Anon-transitory computer readable storage medium storing a program forcausing a computer to execute a control method for controllingtomosynthesis imaging for obtaining a tomosynthesis image from aprojected image group captured by irradiating an object with X-rays froma plurality of different angles by using an X-ray generation unit and anX-ray detection unit, the control method comprising: a setting step ofsetting at least one of projected images of the projected image group asa reject; a limiting step of limiting transmission of data set as areject to an external device, wherein the setting step sets thetomosynthesis image generated by reconstruction using the projectedimage group including at least one of the projected images set as thereject; and a display control step that causes an indication indicatingeach of the tomosynthesis image and the projected image group to bedisplayed and further causes a mark indicating whether or not thecorresponding at least one of the projected images has been set as areject by the setting step to be superimposed on the indication, whereinthe display control step causes an indication corresponding to the atleast one of the projected images set as a reject by the setting step tohave superimposed thereon a mark indicating that the at least one of theprojected images has been set as a reject, wherein the display controlstep causes first imaging information for capturing a projected imagegroup to be displayed in a first display area, and, in response to theprojected image group corresponding to the first imaging informationbeing captured, causes a thumbnail image indicating the projected imagegroup to be displayed in the first display area, and in response to atomosynthesis image based on the projected image group being generated,the display control step causes a thumbnail image of the tomosynthesisimage to be displayed in the first display area.